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A square-shaped patch antenna with high-gain performance and polarization reconfigurability is introduced in this study. This antenna offers the unique capability of seamlessly transitioning between linear polarization (LP) and circular polarization (CP), expanding its versatility in various communication applications. The polarization flexibility is achieved through the strategic integration of two RF switches utilizing p-i-n diodes, strategically positioned within the square slot structure. Through meticulous optimization of the switch placement, the antenna is capable of generating both right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) patterns. Fabrication and testing of the prototype validate the efficacy of the design, showcasing excellent agreement between simulated and measured results. Notably, the antenna demonstrates impressive impedance bandwidths of 5.6 %, 5.2 %, and 6.5 % at a nearly common frequency of 2.7 GHz, coupled with respectable gains of 8.12dBi for LP, 11.19dBic for LHCP, and 10.55dBic for RHCP configurations, respectively. The comprehensive design details, along with extensive experimental and simulated findings, are meticulously presented, underscoring the antenna's remarkable performance and potential for diverse wireless communication scenarios. [ABSTRACT FROM AUTHOR]

This paper presents a reconfigurable bandstop frequency selective surface (R-FSS) design capable of switching across C, X and Ku-bands. The electronic switching mechanism is achieved in real-time through PIN diodes. The combination of rectangular loops is selected as unit-cell and PIN diodes are strategically placed to dynamically adjust the bandstop region. The device operates in three distinct modes corresponding to the activation status of the PIN-diodes. For TE polarization, Mode 1 encompasses the Ku-bandstop (12.64–14.75 GHz), Mode 2 corresponds to the C/X-bandstop (6.62–11.28 GHz), and Mode 3 involves the X-bandstop (9.82–11.63 GHz), whereas X-bandstop characteristic is observed for TM polarization (9.054–––11.29 GHz). In TE polarization, each configuration is defined by specific equivalent circuit models, featuring an inductance in parallel with series L-C resonant circuit, an L-C resonant circuit in parallel with the inductance, and two L-C resonant circuits in parallel, respectively. Additionally, for TM polarization, the configuration incorporates two parallel L-C resonant circuits. A prototype of the proposed R-FSS is fabricated and measured. The results demonstrated effective switching operation across the C, X and Ku-band stopbands, depending on the biasing of the PIN diodes. The experimental outcomes are consistent with the simulation results, affirming the compatibility and functionality of the proposed R-FSS design. [ABSTRACT FROM AUTHOR]

To address the specific requirements of antennas in Unmanned Aerial Vehicle (UAV) joint radar-communication (RadCom) systems, a novel low-profile reconfigurable metantenna with the capability of frequency and pattern reconfiguration is proposed in this paper. The proposed antenna consists of a metasurface layer with 3 × 3 square unit cells and a simple feeding network with two pairs of PIN diodes. Specifically, the designed metantenna has a low profile of 0.064 λ 0 (λ 0 is the free space wavelength at 5.5 GHz). And measured results show that, for the broadside radiation mode, the −10 dB operating bandwidth is about 12.1 %, ranging from 5.05 to 5.7 GHz with a maximum gain of 8.9 dBi. For the conical radiation mode, the −10 dB operating bandwidth is about 21.9 %, ranging from 5.88 to 7.33 GHz with a maximum gain of 6.83 dBi. Given its excellent radiation performance, the metantenna designed for UAV joint RadCom systems holds significant research significance and value in the field of multifunctional reconfigurable antennas. [ABSTRACT FROM AUTHOR]

A method of designing beam-steerable patch antennas with wide stopband suppression is proposed in this article. The wide stopband suppression characteristic is realized by designing suitable parallel coupled lines and open-circuited stubs. The beam steering characteristic is achieved by using a driven patch and two pairs of metal walls vertically placed on both sides of the driven antenna. By controlling the different states of the switching PIN diodes loaded between metal walls, the stable beam steering characteristic can be obtained over the entire operating bandwidth. An experimental antenna is designed and manufactured to validate the approach. The beam steering angles of the simulation and measurement results are ±30°. Moreover, in the three proposed operating states, the out-of-band suppression from 2.6 GHz to 10 GHz is more than 16 dB. The proposed antenna can achieve the characteristic of both wide stopband suppression and beam steering. In addition, the proposed antenna is able to maintain good impedance characteristics during beam steering and maintain stable beam over the entire operating bandwidth. [ABSTRACT FROM AUTHOR]

Reconfigurable MIMO antennas adapt dynamically to changing communication needs and environmental conditions by changing their emission patterns, polarization, and frequency characteristics. By adjusting the antenna configuration, reconfigurable MIMO systems can prevent interference and improve spectral efficiency, resulting in increased data rates and optimal utilization of available frequency ranges. Furthermore, the antenna parameters are optimized to obtain better results and help to enhance the overall efficiency of the model. In this study, an L-shaped reconfigurable band decoupling assisted dual band four port MIMO antenna is designed. The antenna reconfigurability has been obtained from a band stop filter with a pin diode in the proposed design, with four PIN diodes in each individual antenna for improved isolation. The mutual coupling between the antenna elements has been reduced by inserting a DGS to the antenna elements. The presented reconfigurable four-port L-shaped MIMO antenna is applied over 5G and IoT applications. The overall dimensions of the antenna is 40 × 40 × 0.508 m m 3 , which resonates over a dual frequency range between 2.344 GHz for 5G applications and 1.433 GHz for IoT applications. Rogers RT Duroid 5880 substrate with a thickness of 0.508 mm, a dielectric constant of 2.2, a relative permeability of 1, and loss tangents of 0.009 in the proposed design and coplanar waveguide feed line are employed, and an I-shaped stub is used to increase isolation. Defected ground structure (DGS) is used in this work to minimize the antenna mutual coupling issue. [ABSTRACT FROM AUTHOR]

This paper reports a low-profile hybrid reconfigurable antenna for 5G sub-6 GHz applications, measuring 14 × 15 × 0.787 mm3. A hybrid, frequency-and pattern-reconfigurable antenna with a semi-circular patch makes up the design. The Rogers RT5880 substrate, having a dielectric constant of 2.2, is used to build the design. Two PIN diodes are employed in the top layer to reconfigure frequency, and two diodes are used in the bottom layer to achieve pattern reconfigurability. Inverted L-shaped stubs and a defective ground structure (DGS) are put onto the antenna's ground plane. The ground plane uses the DGS to cover the necessary sub-6 GHz frequency spectrum. The suggested design covers two distinct frequency bands having −10 dB impedance bandwidth of 260 MHz for 3.4 GHz-3.6 GHz when the top layer diodes are ON and 270 MHz for 3.6 GHz-3.8 GHz when they are OFF. In addition, the suggested design is manufactured and tested, and the simulation and measurement results show good association. [ABSTRACT FROM AUTHOR]

This work presents a novel proposal for a dual wideband circularly polarized (CP) reconfigurable antenna for wideband wireless communication applications. The circularly polarized characteristic is achieved by introducing a gap in the annular ring, which leads to the generation of traveling waves in circular patterns. The concentric annular ring patch is fed using a tapered 50 Ω microstrip line. Dual wideband characteristics are obtained by incorporating concentric annular rings and additional DGS (defective ground structure) to achieve wideband characteristics. By employing PIN diodes, the proposed approach facilitates reconfiguration, allowing for both left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) in either single or dual wideband operations. The CP antenna exhibits an impressive measured axial ratio bandwidth (ARBW) of 35 % (3438–4900 MHz) and 18.75 % (5154–6252 MHz). The measured return loss bandwidths of the proposed antenna are 18.40 % (3990–4799 MHz) and 35.17 % (5161–7364 MHz). The antenna, fabricated using FR4, is compact in size, measuring 0.56 λ o *0.56 λ o *0.01 λ o , and has a peak gain of 6.33 dBic. The simulated outcomes and hardware measurement findings agreed well. [ABSTRACT FROM AUTHOR]

Phased array communication and radar systems employ vector modulators (VM) to simultaneously control both phase and amplitude. This paper presents an innovative technique to alternate the RF signal into four quadrants using switchable balun based bi-phase modulators. This switchable balun topology offers a compact Printed Circuit Board (PCB) based VM design as an alternative solution to high-dimensional hybrid couplers or reflection-type pin diodes. Thanks to the balun, the VM circuit dimensions are only 12.7 mm × 25.4 mm with wide frequency bandwidth coverage. Additionally, the total power consumption is only 3 mW due to its entirely passive topology. The developed VM consists of a 90° power divider, switchable balun based bi-phase modulators, digitally controlled attenuators (DCA), and an in-phase power combiner. The proposed VM achieves a 360° phase shift without any dead zones and 31.5 dB attenuation in 9:1 operation bandwidth with lower rms phase and amplitude errors than the other previously reported state of the arts. Also, this design exhibits a calculated better than −31 dB rms error vector magnitude (EVM). Detailed characterization results show that the proposed VM can be used in transmit or receive beamforming networks that operate from 2 GHz to 18 GHz. [ABSTRACT FROM AUTHOR]

In this paper, a polarization-insensitive absorber with dual-band tunable absorption intensity is proposed. Two absorption bands are generated by introducing external branches into a ring structure. Since the resistance of the loaded PIN diode changes with bias current, the reflectivity of two absorption bands can be dynamically adjusted from almost 0 dB to less than −10 dB at normal incidence. Inductors are loaded on both sides of the metal structure, which guarantees not only that the units are connected during DC feeding, but also the symmetry of the metal structure in RF band to ensure polarization insensitivity. The mechanisms of dual absorption bands and tunable absorption intensity are revealed through the detailed analysis of resonant modes, equivalent circuit model, surface current, and loss density distribution. A sample prototype has also been fabricated, and the measured results are well consistent with the simulated ones. The proposed absorber has the unique advantage of dynamic tuning of dual-band absorption intensity, making it a versatile choice in modern communication, radar, and stealth systems. [ABSTRACT FROM AUTHOR]

This paper presents a dual-polarized bidirectional electronically reconfigurable beam-steering array (DBSA) for the first time, which integrates the beam-scanning capabilities of both dual-polarized reconfigurable transmitarray and dual-polarized reconfigurable reflectarray. First, a novel phase and direction reconfigurable dual-polarized element is proposed. Four PIN diodes are soldered onto the symmetric transmitting patches to tune the 1-bit transmission phase, while two PIN diodes are soldered onto the reflecting patches to tune the 1-bit reflection phase. By controlling the states of the PIN diodes, the DBSA element can achieve 1-bit reconfigurable phase in both transmission and reflection modes. Second, based on the proposed element, a 100-element DBSA prototype is fabricated and measured. At dual-polarization, the angles of the scanned beams can reach 45 ∘ and 222 ∘ in forward- and backward-spaces. Therefore, the proposed novel method opens a new avenue to designing a dual-polarized electronically reconfigurable spatially fed array antenna with full-space beam-scanning capabilities, and the proposed design is suitable for dual-polarized bidirectional wireless communication applications. [ABSTRACT FROM AUTHOR]

This paper presents the extraction of an equivalent circuit model for PIN diodes and varactors in the millimeter waves. This circuit model is handy for new communication applications involving, for example, electronic beam reconfigurability, where diodes are commonly used. For parameter extraction, the proposed model includes the effects of the device, the pads, and the gap underneath the device. From the measurement at various bias points (varactor) or states (PIN diode), it is possible to extract an equivalent circuit to properly model the behavior of these devices when using them to design reconfigurable elements. The results are validated experimentally, obtaining an excellent agreement between the measurements and the equivalent circuit models in a large frequency band up to 67 GHz. • We propose a broadband parasitic model for PIN diodes and varactors up to 67 GHz. • The results of the analytical circuit show an excellent agreement with measurements. • We demonstrate that parasitic effects must be considered from approximately 40 GHz. • The proposed model can be easily implemented for designing reconfigurable devices. [ABSTRACT FROM AUTHOR]

A two-dimensional (2-D) beam steering pattern reconfigurable antenna with an active partially reflecting surface (PRS) is presented in this paper. The proposed design incorporates a U-slot patch antenna functioning as a radiator and a superstrate composed of an active PRS layer. The PRS superstrate layer consists of 6 × 6 unit cells, divided into four sections, each comprised of 3 × 3 unit cells. To achieve reconfigurability, each unit cell within the PRS layer is loaded with two PIN diodes. Phase inconsistency can be introduced by changing the states of the PIN diode at different sections, which causes the PRS antenna to change the direction of its main beam. By controlling the operating states of PIN diodes within each unit cell, a total of sixteen radiation patterns can be generated. The proposed antenna supports 2-D beam steering in both the x z - and y z -planes, allowing for a maximum steered angle of ± 40°. The performance of the fabricated antenna is experimentally verified at an operating frequency of 3.5 GHz. The proposed antenna is suitable for the 5G NR frequency band n78 and operates within the frequency range of 3.3 to 3.8 GHz. [ABSTRACT FROM AUTHOR]

This paper presents a low-profile wideband omnidirectional antenna with reconfigurable tri-polarization. The proposed antenna is composed of a center-fed circular patch part that generates vertically polarized electromagnetic (EM) waves and a bent-branch connected patch part at the bottom that generates horizontally polarized EM waves. By loading PIN diodes on the symmetrical curved branches, the directions of the current flows on the antenna can be controlled to achieve reconfiguration between left-hand circular polarization (LHCP), right-hand circular polarization (RHCP) and linear polarization (LP). Measurement results show that the overlap bandwidths of − 10-dB impedance and 3-dB axial ratio (AR) of the antenna are 10.87% (2.35–2.62 GHz) and 10.91% (2.34–2.61 GHz) for LHCP and RHCP modes, respectively. Under the LP mode, the − 10-dB impedance bandwidth is 13.44% (2.29–2.62 GHz). The peak gains of the antenna are 4.8 dBic, 4.7 dBic, and 4.9 dBi for the LHCP, RHCP, and LP modes, respectively. Measurement results agree well with the simulation results, verifying the effectiveness of the antenna. [ABSTRACT FROM AUTHOR]

This research work reports the Compound Reconfigurable MIMO Antenna (CRMA) utilizing RF PIN diodes for indoor wireless communication applications. The proposed CRMA comprises a quad-symmetric slotted radiator with a common ground structure. It can perform frequency, polarization and pattern switching at frequency standards such as IEEE 802.11a/b/g/n (2.4/5.5 GHz), IEEE 802.11ax (6 GHz) and 5G/n78 (3.5 GHz). A parasitic element of a modified U-shaped stub is utilized to achieve polarization reconfiguration. Further, to achieve pattern reconfiguration two crossed-shaped slots are implemented. The proposed antenna achieves a bandwidth of 320 MHz at 2.4 GHz, 950 MHz at 3.5 GHz and 1870 MHz at 5.5 GHz. At these resonant frequencies, the antenna is capable of producing both circular and linear polarization with a pattern tilt towards different angular directions such as 30°, 120°, 210°, 300°, 330°, 240°, 150°, 60°. The designed CRMA follows orthogonal orientation and exhibits better diversity performance with ECC < 0.1, DG > 9 dB, TARC < −13 dB and CCL < 0.27 bps/Hz. Also, an Acrylonitrile Butadiene Styrene (ABS) enclosure is designed and fabricated to validate the performance of the antenna with casing, further to analyze the suitability of the antenna for indoor wireless applications. [ABSTRACT FROM AUTHOR]

In this paper, a novel dual-band, dual-sense, polarization reconfigurable dual coupled line square microstrip patch antenna is proposed. It comprises of a diagonal edge truncated square microstrip patch with a dual coupled line structure. The dual-band operation is realized by using dual coupled lines. They also aid in generating dual-sense of circular polarization (CP) at two resonances. The diagonal edge truncated square patch consists of four PIN diodes along with the bias circuit. It realizes a dual-sense of polarization reconfiguration like right-handed circular polarization (RHCP)/left-handed circular polarization (LHCP), linear polarization (LP)/LHCP, RHCP/LP at lower resonance f 1 = 2.4 GHz and higher resonance f 2 = 2.6 GHz respectively for different states of the diodes. The proposed antenna is designed, simulated, fabricated, and experimentally tested for validation. The experimental results of −10 dB reflection coefficient, 3 dB axial ratio for CP, gain, and radiation pattern characteristics at the two bands are acceptable and are found to be in concurrence with simulation results in all the states. The proposed antenna would be useful for multifunctional wireless communication applications. [ABSTRACT FROM AUTHOR]

In numerous remote correspondence frameworks, there is a necessity for light, low-profile receiving wires. These receiving cables don't stand out as much as commonly used metaphorical reflectors. In addition, they are less affected by wind, rain, or snow. One example of a light-weight, low-profile receiving wire is a planar radio wire fused with various microstrip patches. Each individual repair has to be adequately handled in order for this cluster to function as a potent radiator. This goal may be achieved through a variety of methods. In this study, a micro cantilever Micro Electro Mechanical Systems (C-EMS)switch-based recurrence reconfigurable radio wire is designed to achieve various proficient performance boundaries, including decreased inclusion misfortune, great seclusion, extremely high linearity, low influence misfortunes, burns-through little or practically no DC influence, and wide data transmission. At the intermediate repetition of 22 GHz, the switch is designed to operate with a top-to-bottom disconnection of about 54.17 dB. Due to changes in the emanating length of the fixed radio wire operating at different ON/OFF combinations of switches, the receiving wire using MEMS switch exhibits a recurrence shift of 1.5 GHz from the primary case to the subsequent case, whereas the receiving wire using a diode moves the recurrence around the same but is less noise-resistant due to the low PIN diode segregation. [ABSTRACT FROM AUTHOR]

This work presents frequency reconfigurable Wideband Rectangular Dielectric Resonator Antenna (RDRA) using a Machine Learning (ML) approach for 5G (Sub-6 GHz) applications. The concept of ML is integrated with reconfigurable DRA for the first time. A novel approach has been proposed to obtain wideband and frequency reconfigurability. Frequency reconfigurability is achieved electronically (PIN diode switches) and operates in four different configurations, offering a maximum of 76.84 % wide tuning range. Hybrid structure and higher order mode T E 111 and T E 211 modes excitation is responsible for wideband operation. The Extreme Gradient Boosting (XGB) ML algorithm provides more than 90 % accuracy in all configurations for S 11 prediction. [ABSTRACT FROM AUTHOR]

A compact ultra-wideband (UWB) triple mode frequency reconfigurable multiple-input multiple-output (MIMO) antenna with electronically controllable single band elimination properties is presented in this work. The reported antenna comprises of two rotationally symmetric identical modified circular radiators each having tapered microstrip feed lines and separate partial defected ground structures (DGS). The slotted radiating patches consist of C-shaped parasitic strips placed at their centers. Two PIN diode switches were utilized to join and detach the C-shaped strip and slotted circular radiator, and thus total four PIN diodes are employed in the dual-port MIMO configuration to achieve switchable operation between UWB and single band-notched UWB characteristics. The recommended antenna possesses ultrawide bandwidth with Snn ≤ −10 dB except at the rejected bands and attains isolation better than −21 dB in all reconfigurable modes. The proposed MIMO antenna shows good diversity behavior which has been proved through the study of various parameters, such as envelope correlation coefficient (ECC), CCL and diversity gain with values fulfilling the acceptable standard for practical usage. High diversity gain and ECC value below 0.0006 are obtained for all the modes. The suggested antenna structure is ideally suited for ultrawideband MIMO systems with on-demand suppression of WiMAX or WLAN signals. [ABSTRACT FROM AUTHOR]

This paper introduces an ultra-wideband (UWB) dual-element MIMO antenna with reconfigurable band-notched characteristics. The antenna comprises a partial elliptical radiator patch with a partial trapezoidal notched ground and has a fractional bandwidth of 120%. By incorporating two inverted U-shaped slots and three PIN diodes, the antenna can switch between dual, single, and no notches, enabling reconfigurable band notches for WIMAX (3.5 GHz), sub6 5G band (4.5 GHz), and satellite communication band (7.5 GHz). The proposed structure has been extended to a two-element MIMO in a side-by-side arrangement, achieving isolation characteristics below -30 dB over the bandwidth by incorporating stubs between the antenna elements. The MIMO antenna has acceptable diversity performances, and the switching characteristics remain unperturbed. The time-domain behavior shows that the structure can handle impulse signals. The overall substrate dimension of the dual-element MIMO is 1. 4 λ 0 × 0. 7 λ 0 . The simulated and measured results are in good agreement. [ABSTRACT FROM AUTHOR]

This article proposes a flexible metasurface absorber (MA) with reconfigurable absorption intensity in an ultra-wideband spectrum. Due to the utilization of an ultrathin polyimide substrate, the MA is endowed with superior flexibility over previous rigid designs. The pattern of the MA consists of a fourfold symmetrical metal strip and four PIN diodes, which simultaneously activate multiple resonances to generate a wide operating band. By adjusting the voltage of the PIN diodes embedded in the strips, the MA can execute various stages of reconfigurable absorption intensity through varying states of ohmic loss. When the PIN diodes are off, MA is switched to a reflector. In addition, the results of the equivalent circuit simulation confirm the feasibility of the design. Finally, an MA sample is fabricated and measured, and good agreement is obtained between the measured and simulated results. The MA achieves a reconfigurable absorption intensity varies from −16.8 to 0 dB over an ultra-wide frequency range of 5.6–16.98 GHz, with relative bandwidth up to 100.8%. As expected, the designed MA features excellent characteristics both in plane and curved states. [ABSTRACT FROM AUTHOR]

A compact planar monopole elliptical UWB antenna with a microstrip band-stop filter using a Slot-Type Split-Ring Resonator (ST-SRR) is analyzed and presented in this paper. In order to improve the impedance matching and operating bandwidth of the proposed antenna, a partial defected ground plan is utilized. The ST-SRR structure is inserted into the center of the feed line of the UWB antenna to achieve notch band characteristics to reject interference with the wireless local area network (WLAN) IEEE802.11a/h/j/n (5.15–5.35 GHz, 5.25–5.35 GHz, 5.47–5.725 GHz, 5.725–5.825 GHz) and Wi-Max (IEEE802.16 3.30–3.80 GHz). A pin diode is inserted in the ST-SRR structure in order to achieve reconfigurability in the notch band function. The measured result shows that the proposed antenna operates over 2.7 to 14.9 GHz with a fractional bandwidth of 138.63% for S 11 ≤ −10 dB. By controlling the PIN diode at OFF and ON states, the notch bands of the proposed UWB can be switched in the range of 3.43–3.75 GHz and 4.87–6.40 GHz, respectively. Good agreement between the simulated and measured results is achieved. The obtained results show that the proposed antenna is a good candidate for reconfigurable UWB communication applications. [ABSTRACT FROM AUTHOR]

Abstract A compact (33 × 16 × 1.6 mm3) and novel shaped hexa-band frequency-reconfigurable antenna with a very wide tuning band is proposed. The proposed antenna operates at two single band modes (i.e., 3.5 GHz and 4.8 GHz) and two dual band modes (i.e., 2.10 GHz, 4.15 GHz and 2.4 GHz, 5.2 GHz) depending upon the switching states. The lumped elements are used in the simulation environment to achieve tunable capacitance, which is responsible for frequency reconfigurability. The measured tuning capability of the fabricated antenna ranges from 2.1 to 5.2 GHz. The proposed antenna has a VSWR < 1.3 for all the resonant bands. The radiation efficiency of the proposed structure ranges from 80.41% to 96% at the corresponding frequencies. The far field and the scattering parameters of the proposed antenna are analyzed using Computer Simulation Technology (CST) Microwave Studio 2014. The designed antenna, due to its compact and affordable geometry, can be easily integrated in the modern communication devices such as smart phones, laptops and other portable electronic devices. A prototype of the designed antenna is fabricated and measured using PIN diode switches to validate the simulation results. The proposed reconfigurable antenna demonstrates a reasonable agreement between the measured and simulated results. [ABSTRACT FROM AUTHOR]

A novel EM (electromagnetic) design of low observable antenna using active hybrid-element frequency selective surface (FSS) as ground plane is presented in this paper for stealth applications. The EM characteristics of active hybrid-element FSS structure are reconfigured from reflecting mode to transmitting mode and vice versa by switching ON and OFF the PIN diode at 10 GHz. In ON state of diode (reflection mode), the FSS structure shows extremely less transmission (<−40 dB), which corroborates its suitability for ground plane of antenna. In OFF state of diode (transmission mode), it exhibits bandpass response over the frequency range 9.3–10.7 GHz corresponding to very less power loss (<−0.42 dB). Further, a low observable microstrip patch antenna (MPA) is designed using proposed FSS structure as ground plane and its EM characteristics are studied using commercial software package. In ON state of diode, the FSS-based MPA is observed to perform as typical MPA and its out-of-band radar cross section (RCS) also reduces as well. In OFF state of diode, FSS-based antenna does not radiate while passes EM signal impinging on its structure in result reduces significantly in-band RCS (up to 15.8 dBmm 2 ) as compared to conventional MPA. Finally, a prototype active FSS-based antenna is fabricated and measured for proof-of-the concept. [ABSTRACT FROM AUTHOR]

In this paper, a circular polarization-agile and beam switching enabled reconfigurable cavity-backed antenna having the ability to steer its radiation beam in different directions is presented. The antenna consists of two E-shaped driven patches, a tunable phase shifter integrated with PIN diodes for pattern switching and four switchable feeding probes for implementing polarization agility. The proposed antenna can simultaneously change its polarization and pattern. Beam switching and polarization agility are independently controlled by altering the OFF-ON states of diodes loaded on the feed network and switchable feeding probes. For validity of the proposed concept, the antenna prototype is fabricated and tested. The proposed antenna has measured impedance bandwidth (S 11 < -10 dB) and 3 dB axial ratio bandwidths of 23% and 17.4% respectively for all states over the frequency range 4.7–5.6 GHz. The measured and simulation results show that the antenna can scan up to ± 30° with five reconfigurable beams and two polarizations states for each reconfigurable beam. [ABSTRACT FROM AUTHOR]

A compact dual-band circularly polarized antenna with a characteristic of pattern reconfiguration is proposed for S-band satellite handsets. The antenna works as a patch antenna in a channel shape with no ground beneath reaching an overall size of 0.55λ × 0.14λ × 0.1λ. The dual-band performance is realized through multi-branch slots of the patch. The antenna mainly consists of a channel metal patch, a channel dielectric, and a simple feeding network. The overall shape of slot can be changed by the PIN diode on the patch to adjust the surface current direction, which in turn achieves 180° switching of the left-hand circularly polarized radiation beam direction. In addition, by combining the quadrifilar helical antenna, which is switchable in the end-fire beam direction, the designed antenna can realize the switching of four main beam directions to achieve 360° 3D spatial coverage. The proposed antenna is fabricated and measured to verify the proposed design. The test results show that the designed antenna obtains circularly polarized radiating characteristics in S-band with the center frequency of 1.98 GHz and 2.2 GHz, and the test results and simulation results are basically consistent, which indicates the superior performance of the designed antenna. [ABSTRACT FROM AUTHOR]

A linear polarization converter based on multi-mode active metasurface is proposed to achieve wideband/dual-band, function-switch, low profile, filter and reflection, including two slot-loaded right-angle triangular resonators connected by two PIN diodes. The switchable function of the linear polarization converter between wideband and dual-band is realized by controlling the OFF/ON states of the diodes. By detailed analysis of the field/current distribution and polarization components in different modes of the multi-mode resonator unit, the filtering characteristic and magnetic-resonant-based polarization conversion mechanism between wideband and dual-band are revealed. A function-switchable filtering reflective linear polarization converter is designed, fabricated, and measured, presenting single bandwidth of 6.43–10.16 GHz, dual bandwidths of 6.08–6.39 GHz, and 11.7–12.54 GHz in the OFF- and ON-state, respectively. In both states, the polarization conversion ratios both exceed 90 %. Results show that the proposed reflective linear polarization converter has excellent switchable function, low profile and filtering linear polarization conversion. [ABSTRACT FROM AUTHOR]

This paper presents a compact pattern reconfigurable antenna for sub-6 GHz (4.8 GHz-5 GHz) applications. The proposed antenna consists of a quarter-wavelength radiator with two circular slot-loaded oval-shaped patches on both sides of the radiator. The antenna's ground plane is loaded with an inverted l -shaped structure. Two PIN diodes are used to switch the direction of radiation. Good agreement between simulated and measured results is obtained. The −10 dB impedance bandwidth of the proposed design is 370 MHz. The peak gain is 5.5dBi, and efficiency is 82 % in different diode states. The proposed antenna is then analyzed with the Nordic nRF9160 DK board to check the design reliability. [ABSTRACT FROM AUTHOR]

This paper proposes a circularly polarized (CP) three-element multiple-input multiple-output (MIMO) antenna system with diversity and polarization reconfigurability techniques for wireless local-area network (WLAN) applications. The proposed MIMO antenna system employs two CP antennas with endfire characteristics and a broadside slot antenna. The polarization reconfigurability technique is achieved using pin diodes in all three antenna elements. Additionally, the three antennas have distinct directional radiation patterns, improving the MIMO antenna system's diversity performance. The three-element MIMO antenna system is fabricated for validation, and antenna parameters are measured. For all the states, the proposed antenna provides good antenna characteristics for the WLAN frequency band (5.15 GHz − 5.35 GHz). The three-element MIMO antenna exhibits good port-to-port isolation, and MIMO parameters like total active reflection coefficient (TARC), channel capacity loss (CCL), envelope correlation coefficient (ECC) and diversity gain (DG) are within the acceptable range. [ABSTRACT FROM AUTHOR]

In this paper, a novel polarization and frequency reconfigurable microstrip patch antenna which can switch between vertical and horizontal linear polarizations, left hand and right hand circular polarizations at two WLAN frequencies is presented. The orthogonal linear polarizations are achieved by a square microstrip patch antenna fed by two ports on adjacent sides. By introducing corner truncated perturbation on opposite corners of right diagonal of a square patch, orthogonal circular polarizations are achieved. By controlling the bias voltage of two PIN diodes loaded at perturbed corners, a single structure can achieve quad polarization states. Furthermore, by superimposing a square ring slot into the corner truncated square patch and incorporating four PIN diodes into the square ring slot, quad polarization are achieved at dual frequencies. Simulated and measured results indicate that the antenna can achieve quad polarization at two WLAN bands (5.15–5.35 GHz) and (5.75–5.85 GHz). The proposed antenna is simple, has low profile and can be scaled easily for other frequencies. [ABSTRACT FROM AUTHOR]

In this paper, a novel single feed frequency and polarization reconfigurable microstrip patch antenna is presented. This antenna mainly comprises of a corner truncated square patch with a rectangular ring slot, eight PIN diodes and six conductive pads. Four PIN diodes are placed symmetrically in the rectangular ring slot to bridge the gap and to switch the frequency between WLAN bands resonating at 5.2G Hz and 5.8G Hz. Four PIN diodes connect the corner truncated square patch to parasitic triangular conductors. PIN diodes are used to switch the polarization between linear, right hand circular and left hand circular at each frequency. When compared to conventional patch, the proposed design provides a size reduction of 12% at 5.2G Hz, and 30% at 5.8G Hz. The simulated reflection coefficient and radiation patterns are presented and compared with the experimental data. This antenna finds applications for modern wireless communication system. [ABSTRACT FROM AUTHOR]

A simple design of a compact radiation-pattern reconfigurable monopole antenna with different states is proposed. The antenna switches between four radiation patterns by introducing two parasitic elements, which can be controlled by activating or deactivating two p-i-n diodes. The antenna presents two opposite-direction unidirectional modes, one bidirectional mode, and one omnidirectional mode. Few lumped components are used in the DC bias network, reducing the fabrication cost and antenna complexity. An antenna prototype is fabricated and tested to validate the proposed approach. The common operating frequency band measured realized gain and realized efficiency ranging from 3.36 GHz to 3.6 GHz, 2.13 dBi to 4.93 dBi, and 62% to 82%, respectively. The antenna presents the benefits of a low profile, simple DC bias, and the ability to suppress radiations in unwanted directions. Therefore, the antenna can be easily integrated and used in different wireless systems requiring pattern diversity, for instance, in Sub-6 GHz Internet of Things (IoT) Applications. [ABSTRACT FROM AUTHOR]

A low sidelobe leaky wave antenna (LWA) based on Spoof Surface Plasmon Polariton (SSPP) with switchable right/left-handed circular polarization (CP) and linear polarization (LP) radiation function by controlling the status of two PIN diodes is proposed. Two symmetrical SSPP transmission lines (TLs) are connected through two PIN diodes, and the ON–OFF of diodes constitute three different transmission modes. Two rows of the tapered arranged elliptical patches are loaded periodically around the TL to break the original stable transmission structure for radiation, and suppress the antenna sidelobe levels to less than −10 dB. After experimental verification, the reconfigurable antenna can reach three functionalities: (1) Mode 1: 22°right-handed CP beam scanning from 8.3 to 9.0 GHz; (2) Mode 2: 22°left-handed CP beam scanning from 8.3 to 9.0 GHz; (3) Mode 3: 78°LP beam scanning from 8.3 to 10.3 GHz. In Mode 1 and 2, the axial ratios (ARs) are lower than 3 dB, and the average gain can reach 11.6 dBi, while 13.4 dBi in Mode 3. A leaky wave antenna that can switch the radiation function of linear/circular polarization with favorable performance characteristics, such as wide scanning range, high gain, low sidelobe levels, and high efficiency, makes it an ideal candidate for wireless communication. [ABSTRACT FROM AUTHOR]

• Broadband circularly polarized antennas with enhanced CP gain & improved radiation are important from application perspectives. • Proposed antenna exhibits effective attributes & integration with active elements leads to polarization reconfigurability. • Concurrent analysis about CP relates understanding with the classical electromagnetics. • The proposed implicit technique in form of a single-layered metasurface is capable of improving performance trade-offs. • Elaboration of physical insights & theoretical intuition provide support to the generic solution. A single-layered metasurface-loaded high-gain & broadband polarization reconfigurable λ o /4 printed monopole antenna is investigated in this article. The proposed antenna configuration comprises of Y-shaped radiating monopole over partial ground plane with the extended twin parasitic conducting strips (PCS), is loaded with a single-layered metasurface (MS) reflector. To attain circular polarization (CP) characteristics, a BAR 50-02 V PIN Diode from Infineon is used to short the partial ground plane and one of the twin parasitic conducting strips (PCS-L). By utilizing the grid-slotted sub patches on the rectangular reflecting surfaces of MS layer with a volumetric dimension of 2λ o × 1.65λ o × 0.02λ o , is placed just below Y-shaped monopole radiator (PYMA) at a height of 0.33λ o , in which broadened impedance (IBW) and 3-dB axial ratio bandwidth (ARBW) with the enhanced CP antenna gain are achieved. Finally, proposed prototype of 1.33λ o × 0.9λ o × 0.02λ o , where λ o = 5 GHz is fabricated and measured. It offers an measured IBW of 48.45 % (3.57–5.85 GHz), ARBW of 25.96 % (4.19–5.44 GHz) and the CP antenna gain of >8.35 dBic with antenna efficiency of >75 % in the desired operating bands. From the above results, the performance of single-layered metasurface-inspired polarization reconfigurable antenna confirms its suitability for hybrid wireless applications and also, it can be extended towards the scope of designing efficient RF energy harvesting system. [ABSTRACT FROM AUTHOR]

In this study, a reconfigurable conformal antenna suitable for Wireless Capsule Endoscopy (WCE) is proposed. The proposed antenna achieves reconfigurable omnidirectional radiation regardless of its orientation and position inside the Gastrointestinal (GI) tract. The reconfigurable omnidirectional radiation pattern is obtained using two PIN diodes, which provide four stats, and with the aid of a microcontroller inside the capsule, a decision can be made to decide which state gives the higher gain simultaneously. The capsule antenna is designed as a meandered Inverted-F antenna (IFA) operating at 433 MHz on Rogers 5880 laminate and attains a volume of 30 × 15 × 0.254 mm3 in planar form, and the conformal form fits inside a capsule with a length of 26 mm and a diameter of 12 mm. The proposed capsule antenna is simulated in muscle, stomach, and colon homogenous boxes in different orientations. It achieves a realized gain of −33.64 dBi inside a colon cube of length 100 mm. The proposed antenna is then tested inside a voxel model. Moreover, the robustness of the communication system containing the capsule antenna is satisfied. When the maximum input power (11 mW) is calculated from the Specific Absorption Ratio (SAR) in the colon, the link Carrier-to-Noise ratio (C/N o) is higher than the required C/N o for 4 Mbps data rate and at distances up to 3 m. The proposed capsule antenna's performance is validated by fabrication and measuring it inside a muscle phantom. [ABSTRACT FROM AUTHOR]

• Design of three quarter-wavelength stubs for specific frequencies. • Reconfigure the filter to operate in different passbands by making the stubs either open or short-ended through P-I-N Diodes. • Deriving the ABCD Parameters and S-parameters for the transmission line circuit of the proposed filter to generate the results theoretically. • Generate the Transmission Zeros through higher-order responses to enhance the.stopband rejection. In this article, the design of a compact reconfigurable bandpass filter using quarter-wavelength open/short-ended stubs for Ultra-Wideband applications is presented. The filter has been designed using three quarter wavelength stubs. Stubs are designed for specific frequencies. At the designed frequency, the quarter-wavelength stub exhibits either bandpass or bandstop characteristics according to its short or open-circuited configuration, respectively. The proposed filter generates five passbands and twelve transmission zeros through four reconfigurable states. The direct and higher-order responses of each stub are effectively utilized to achieve five passbands, which are at 3.8 GHz – 7.8 GHz (notch band from 5.9 GHz to 6.4 GHz), 2.8 GHz − 5.9 GHz, 5.2 GHz − 8.0 GHz, 5.2 GHz – 5.88 GHz, and 1.7 GHz to 4.1 GHz. The filter is designed on FR-4 substrate and simulated in High Frequency Structure Simulator. To analytically validate the results, an equivalent transmission line circuit is extracted, and ABCD parameters have been derived. The S-parameters are derived from the ABCD parameters and plotted through MATLAB software. The designed filter is fabricated and tested. There is a good agreement between simulated and measured responses. The overall size of the filter is 24 × 15 × 0.8 mm3. [ABSTRACT FROM AUTHOR]

A rectangular reconfigurable, 1 × 8 linear array antenna has been designed and developed for tri-band, S, C and X-band applications. The antenna is excited along with the combination of PIN diodes to achieve the frequency and pattern reconfigurability. The design has been validated using a linear array fabricated on RT duroid 5880 substrate ( ɛ r = 2.2). The individual patch antenna consists of nine rectangular radiating elements. The measured results are having a good agreement with the simulated one. [ABSTRACT FROM AUTHOR]

This article presents the design of a 2 × 1 reconfigurable beam steering array. We have used a simple and cost-effective technique to implement the concept of reconfigurability by applying the phase difference between the two elements of the antenna array using the RF PIN diodes. A demonstration antenna has been simulated, fabricated, and measured to verify the proposed concept. This antenna array is designed on an FR4 substrate in which the two elements are fed through a microstrip line. The measured results indicate that the proposed antenna can rotate its radiation pattern between −36° to +36° with respect to the antenna broadside within the overlapping bandwidth from 5.12 GHz to 5.41 GHz. The simulated and measured results are found in good agreement. The advantage of the proposed design is that it provides a larger steering angle using the same profile as other references with minimal design complexities due to its planar structure. [ABSTRACT FROM AUTHOR]

In this work, a miniaturized multiple-input-multiple-output (MIMO) antenna with frequency agility is designed and developed for 1.8 GHz, 2.4 GHz, and 3.5 GHz application bands. The prospective antenna element comprised of a modified ground surface and a microstrip-line-fed slotted radiator (SR) loaded with a modified-electric inductive capacitive (m-ELC) meta-resonator. In order to achieve frequency reconfigurability, a PIN diode is integrated between the SR and the m-ELC resonator. The size of the antenna element is 0.19 λ 0 × 0.18 λ 0 , and the size of the MIMO antenna is 0.39 λ 0 × 0.36 λ 0 , where λ 0 is the smallest resonating frequency. In the proposed MIMO antenna, only four PIN diodes are required to provide frequency reconfigurability, and it does not require an additional impedance matching network. [ABSTRACT FROM AUTHOR]

This paper presents the design and characterization of the four-port MIMO antenna constructed using filtering antenna elements. The proposed antenna consists of a UWB antenna whose feedline is integrated with low-pass and bandpass filter sections. The UWB antenna is constructed using a novel radiating patch with a sufficiently large radiating aperture to achieve better gain characteristics. The low-pass filter is constructed using a stepped impedance slotted line section with a passband covering the lower edge of the UWB band. On the other hand, the bandpass filter is designed using hair-pin coupled line sections to cover the mid-frequency ranges of the UWB band. The proposed antenna operates in three modes and the bandwidth selection is accomplished using PIN diodes. By properly choosing the excitation voltage and the proposed antenna can work in UWB mode (2.1 GHz–10 GHz) for low power applications, IoT/WLAN mode (2.1 GHz–3.9 GHz), WLAN/DSRC mode (5–6.5 GHz). The proposed filtering antenna is extended to construct a four-port vertically polarized antenna to improve the link reliability. The MIMO metrics of the proposed four-port antenna is evaluated and the results are presented. The prototype MIMO antenna is fabricated and tested for impedance and radiation characteristics. The measured antenna gain is greater than 3.5 dBi in all four ports. Furthermore, the onboard performance of the proposed antenna is evaluated and the results are presented. [ABSTRACT FROM AUTHOR]

In this paper, an equilateral triangle inspired a novel triple-band multiple-input-multiple-output (MIMO) antenna is reported for L and S-band applications. The antenna elements are very closely placed at a separation of λ max / 20 with isolation better than −15 dB. The proposed antenna operates in 1.06–1.24, 1.52–2.13, and 2.19–2.63 GHz in the first, second, and third bands respectively covering most of the communication bands. The triple-band operation is obtained by extending the electrical length of the main triangular radiator using two pin diode switches and slotted triangular parasitic patches. The bandwidth of the first and second bands can be tuned between 90 and 110 MHz, and 150, 440, and 610 MHz respectively. The bandwidth of the third band can be tuned between 390 and 440 MHz. The antenna has a reasonable gain of above 3.8 dBi, co and cross-polarization isolation better than 14 dB and quasi-omnidirectional radiation pattern. The envelope-correlation-coefficient (ECC) is well below 0.5 and diversity gain (DG) more than 9.5 dB in all operating modes. The proposed work is validated by prototyping and the measurement results. [ABSTRACT FROM AUTHOR]

This work reports on an Active Meta-Surface (AMS) that is capable of switching between the two WLAN bands at 2.4 GHz and 5.0 GHz. The switching is carried out in real-time electronically with the help of PIN diodes. The unit element of the surface is built out of a vertical strip resonator with circular extensions on both edges. A section of the design is connected or disconnected from the main resonator with the help of PIN diodes to realize the switching mechanism. The design is highly miniaturized with the unit element size of 0.125 λ o at the lower frequency band. Each unit element employs a pair of PIN diodes which is biased through a serial biasing mechanism thus requiring no additional DC lines along with every unit element. This simple biasing scheme adds no parasitics, hence the response with lumped components remains stable. The equivalent circuit model of the proposed design is also created for a better understanding of distributed reactances. The design achieves excellent agreement between the simulated and measured results and the angular stability of the design is intact up to 60° incident angles. [ABSTRACT FROM AUTHOR]

The design and characteristics of a PIN diode based tunable Frequency Selective Surface (FSS) is provided. Spatial filtering, polarization filtering and polarization control are all features the FSS exhibits in the considered 2-14 GHz frequency band. The proper symmetries required for the different features are explained and controlled by a holistic approach that includes the effects of the biasing network in the design. Symmetry breaking due to the presence of the biasing network used to bias the active elements are compensated by predistorsion of the initial geometry of the main structure that presents rotational symmetry. The proof of concept presented here allows extending the method to achieve proper design goals. [ABSTRACT FROM AUTHOR]

This paper presents the numerical approach for dual-band frequency reconfigurable microstrip antenna. The proposed antenna is the combination of rectangular patch and slot, which is separated by a narrow gap. Three RF PIN diodes are brought together to fill the gap and achieve dual-band frequency reconfigurability. It resonates at 1.1753 GHz (1.16 GHz—1.19 GHz) and 2.4895 GHz (2.47 GHz—2.51 GHz) with maximum gain of 1.20 dBi and 8.515 dBi, respectively. The antenna provides stable unidirectional radiation patterns at both the resonant frequencies during frequency reconfiguration operation. The proposed analytical model offers physical insight into the working of this antenna and can also be used to predict frequency switching before full-wave analysis is performed. The prototype is fabricated and compared with simulated results and is suitable for wireless communication systems especially for Indian Regional Navigation Satellite System (IRNSS) receiver. [ABSTRACT FROM AUTHOR]

The article presents a concentric circle compound reconfigurable (frequency, polarization, and pattern) microstrip antenna for lower-S band (2.0 GHz-3.0 GHz) applications. Varying the capacitance of four varactor diodes from 4.15pF (0 V) to 0.94pF (6 V), the resonant frequency of the antenna can be tuned from 2.10 GHz to 2.90 GHz (34.52% tunable bandwidth). These diodes are incorporated to bridge the gap between the circle and ring of concentric geometry. The arc slots and C-shape wings are used for polarization and pattern reconfiguration, respectively. The arc slots are etched from the edge of circle geometry and loaded with RF PIN diodes to provide the different polarization states: linear polarization, left-hand circular polarization (LHCP), and right-hand circular polarization (RHCP). Simultaneously, the pattern reconfigurability can be attained with C-shape wings, placed around the concentric circle geometry; hence, patterns are tilt at 0 ° and ± 50 °. The pattern reconfigurability also controlled through the RF PIN diodes. The designed antenna is experimentally verified and shows the maximum gain of 4.31 dBic and 4.04 dBi in polarization and pattern reconfigurable mode, respectively. Besides, it provides an excellent axial ratio (< 3 dB) and stable radiation patterns. Therefore, the proposed compound reconfigurable antenna can be served for a future communication system and improves the signal quality without any destruction. [ABSTRACT FROM AUTHOR]

In recent days, many slot and patch antennas are being developed for various applications. The proposed work suggests a V-shaped small dimension frequency reconfigurable antenna configuration for WLAN and ISM band applications. The proposed antenna is 16mmx16mm in size and is switchable from one frequency band to another. The frequency reconfiguration characteristics of the antenna are achieved by connecting PIN diodes in the ground, thus creates the antenna to switch the frequencies at 5.5–6 GHz (BW = 8.6%, f o = 5.8 GHz), 4.6–5.6 GHz (BW = 18%, f o = 5.3 GHz),4.6–5.7 GHz (BW = 20.7%, f o = 5.3 GHz), 4.6–4.7 GHz (BW = 2%, f o = 4.66 GHz),4.8–5.5 GHz (BW = 13.4 %, f o = 5.2 GHz). The proposed work uses two 4.5 mm width and 0.25 mm length strips respectively and an impedance matching section of 1.75mmx2mm for feeding the antenna. The gain of the antenna can be improved by reducing the ground area to 1 mm. The PIN diode switches can be controlled by DC bias voltage that is applied through RF chokes. The V-shaped long wire microstrip resonant antenna is fabricated and the parameters are measured experimentally. The compared experimental results with simulated results exhibit maximum antenna gain of 6dBi at 5.3GHz and minimum antenna gain of 3.4dBi at 4.66 GHz respectively. [ABSTRACT FROM AUTHOR]

The manuscript represents an innovative frequency reconfigurable metamaterial-based microstrip patch antenna. The proposed structure provides frequency tunability for multiple bands by using a PIN diode as a switch. The performance of the proposed antenna structure is simulated, fabricate, and compared for copper and liquid (water-sea) based split-ring resonator (SRR). The tooth is added to the outer of the split-ring resonator for gain enhancement and better frequency tunability. Frequency tunability is achieved by connecting the patch antenna with a PIN diode that reduces the size of the antenna. Five switching modes (all switch off, one switch on, two switches on, three switch on and all switch off) of the proposed antenna structure is presented and their reflectance response (s 11), the number of bands, bandwidth, directivity, and total gain is compared for copper and liquid (water-sea) structure with and without a tooth. Results of Fabricated structure and simulated also compared. Frequency tunability is observed for a range of 3 GHz to 9 GHz. The proposed antenna is useful for a weather forecast, satellite communication, and raw satellite feed and many more. [ABSTRACT FROM AUTHOR]

A novel reconfigurable fractal ground loaded monopole antenna with p-i-n diode switching and metamaterial as superstrate for gain and bandwidth enhancement is reported. The proposed structure is a CPW-fed monopole antenna with a Minkowski fractal square ring loaded in the ground plane. The integration of p-i-n diode helps in achieving frequency reconfigurability. The antenna with diode OFF operates at 1.4 GHz, 2.1 GHz, 3.7 GHz, 7.6 GHz and 8.9 GHz. But, with diode switched ON, the resonating frequencies shift to 1.4 GHz, 3.4 GHz, 5.45 GHz, 7.86 GHz and 9.52 GHz respectively. When a metamaterial superstrate is placed on top of the monopole radiator, the respective −10 dB impedance bandwidth enhancement of 1.4%, 28%, 18%, 8.3% and 6.3% is obtained. Furthermore, the respective peak gain of 8.37 dB, 8.67 dB, 5.26 dB, 16.09 dB and 21.58 dB are obtained that justifies the shift of operating bands. The simulation results agree well over the experimental findings. [ABSTRACT FROM AUTHOR]

A pattern reconfigurable antenna offers diverse pattern configurations and beam steering to cater the congested signal environment problem while maintaining the performances and operating frequency, as well as increasing the signal and data security. The pattern reconfigurable antenna using EBG structure is presented in this paper for beam-steering configurations. Most of the previous works proposed the PIN diode on the radiating patches, which caused the degradation of its performances. In this work, the structure offers good efficiency as the RF switches are not embedded to the radiating patches. A dual-band slotted pattern reconfigurable antenna using EBG structure is designed and analyzed. The EBG patches are located at the right and left of the radiating edge of the antenna. The EBG is designed so that its surface wave of band gap covers the radiation of the antenna. As a result, the surface waves excited by the patch antenna are prohibited from propagating by the EBG and caused the radiation pattern to be tilted to another side. The operating frequency of the proposed antenna is 2.45 GHz and 5.8 GHz for the dual-band antenna. The proposed antenna is capable of having beam shifting at three different angles (0°, +26°, and −26°). [ABSTRACT FROM AUTHOR]

A low profile frequency reconfigurable antenna for WBAN applications is reported. The presented antenna design utilizes switching characteristics of PIN diode to achieve frequency reconfigurability. The dimension of the proposed antenna is 0.136 λ 0 × 0.131 λ 0 × 0.001 λ 0. The modified loop-shaped resonator, U shaped stub, and Mirrored F shaped strip provides an independent resonance for three distinct frequency bands. The application bands selected are 1.575 GHz (Global Positioning System), 2.45 GHz (Industrial, Scientific and Medical bands), and 5.2 GHz (Industrial, Scientific and Medical bands/Wireless Fidelity). The percentage bandwidth obtained is 3.17/1.83/2.69% at the said operating frequencies respectively. The simulated gain and total efficiencies are 3.26/3.47/4.04 dBi and 82/85/88% respectively. The directional radiation pattern obtained is highly suitable for off-body communication. The SAR is simulated to validate its suitability for wearable applications. The performance metrics of the fabricated prototype antenna is validated using Measurements. [ABSTRACT FROM AUTHOR]

The paper presents the design of a frequency and pattern reconfigurable rectangular patch antenna using a single PIN diode switch. The use of single PIN diode reduces the complexity of the biasing network required for the diode. The proposed antenna can work in two different modes and resonates at 2.47 GHz, 3.8 GHz, and 5.36 GHz with the capability to change the radiation pattern. In this design biasing lines required for biasing of the diode are placed away from the radiating structure and the pattern search algorithm is used for the optimization of antenna feed for achieving impedance matching. These are the two improvisations made in the presented design as compared to the existing designs in literature. [ABSTRACT FROM AUTHOR]