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The research article outlines the evolution of a quad-element Luna-shaped UWB MIMO with enhanced isolation and gain using novel decoupling networks. The described MIMO module is tailored on a FR4 substrate of area 45 × 45 mm2 (0.378 λ0 × 0.378 λ0), where λ0 is estimated at 2.52 GHz, and 7 mm (0.0588 λ0) element to element separation between the radiators. It has 4 Luna-shaped radiators. The results achieved are S11 ≤ − 10 dB over the band 2.52–11.10 GHz, S21 ≤ − 20.75 dB, and S31 ≤ − 20.10 dB. The peak gain is 6.6 dBi, maximum efficiency is 98%, ECC ≤ 0.15, TARC ≤ − 10 dB, DG ≤ 10, MEG ratio ≈ 1, and CCL < 0.3 bps/Hz. This MIMO module is simulated by ANSYS HFSS and also measured results are presented. [ABSTRACT FROM AUTHOR]

A high-gain, low-profile, and compact-size single-port leaky-wave antenna powered by spoof surface plasmon polaritons (SSPPs) based line is proposed. The proposed leaky-wave antenna is implemented using a variable-width strip dipole on either side of the spoof surface plasmon polaritons line. The designed antenna consists of a coplanar waveguide (CPW), a transition section, and a strip dipole-loaded SSPPs line. To validate the simulation results, a prototype of the single-port leaky-wave antenna is fabricated and measured. The simulation and measured results are in unison. The designed antenna covers the frequency range of 6.18 - 11.40 GHz. The single-port antenna provides the beam-scanning span of 55 ∘ (- 32 ∘ to + 23 ∘) with a significant gain in the broadside direction. The average realized gain in the scanning range is 11.05 dBi, while the peak realized gain and radiation efficiency are 13.8 dBi and 95%, respectively. The designed antenna is intended to be used as a low-profile antenna for radar and wireless communications. [ABSTRACT FROM AUTHOR]

A compact two‐element multiple‐input‐multiple‐output (MIMO) antenna system with improved impedance matching and isolation is presented for future sub‐6 GHz 5G applications. The two identical tapered microstrip line fed modified rhombus‐shaped radiating elements are placed in the same orientation at a compact substrate area of 0.24λ0 × 0.42λ0 (where, λ0 at 3.6 GHz) on a shared rectangular ground. A remodeled T‐shaped ground stub is placed between a pair of radiating element to achieve improved impedance bandwidth and isolation. Further, a split U‐shaped stub connected to center of each radiating element to achieve the desired resonant frequency of 3.6 GHz. The proposed antenna covers a −10 dB operating band of 3.34 to 3.87 GHz (530 MHz) with more than 20 dB isolation between a pair of elements. MIMO performances are also analyzed and experimentally validated. The measured performances of a prototype are found in good agreement with simulated performances. Further, the simulation study is carried out to see the effect of housing and extended ground plane on two‐element MIMO antenna for practical application. An idea of realization of 12‐element MIMO is also studied using the proposed two‐element MIMO antenna. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel dual-band antenna for radio frequency identification tag is proposed for ultra high frequency (UHF: 915 MHz) and super high frequency (SHF: 2450 MHz) bands. The proposed tag antenna is a single sided dual-antenna structure, designed on the grounded (metallic) dielectric substrate. The proposed tag antenna can be used on any kind of surfaces including metals without severe performance degradation due to its metallic ground plane. At UHF band, proposed tag antenna works as dual-antenna structure. In the dual-antenna structure, one antenna works for receiving and another for backscattering. Due to separate backscatterer, the maximum differential radar cross section improved and results in the enhancement of the maximum read range. Whereas at SHF band, proposed antenna works as conventional single antenna structure and during operations it switches between receiving and backscattering modes. The proposed antenna consists of a meandered line antenna and a rectangular patch antenna loaded with an F-shaped and an inverted L-shaped slots. The S-parameters are measured by means of differential probe technique. Simulated and measured results are observed in good agreement. The read range is observed about 5 and 6 m at 915 and 2450 MHz, respectively. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:640-650, 2016. [ABSTRACT FROM AUTHOR]

ABSTRACT A low profile triband compact multiple input multiple output (MIMO) antenna operating at WLAN, WiMAX, and HIPERLAN bands is presented. The proposed MIMO antenna consists of two planar inverted-F antenna elements located at the top two corners of printed circuit board (PCB). Dimensions of each antenna elements are reduced substantially by employing a meandered line and folded patch structure so that it occupies a small volume of 9 × 8.8 × 5.4 mm3. The proposed antenna consists of three arms namely, Main arm, Side arm 1, and Side arm 2. Each individual arm resonates corresponding to the λ/4 electrical length. Characterization of the antenna is carried out in the mobile environment as well as in user proximity. In the presence of mobile environment which includes liquid crystal display (LCD), Battery, RF components, and plastic housing, the isolation as well as reflection coefficient parameters deteriorated. To avoid the aggravation of S-parameters, two nonradiating folded shorting strips are connected between each antenna element and ground plane of PCB. This folded shorting strip not only improves the isolation between ports but also prevent the deterioration of reflection coefficient parameter. The total efficiency, envelope correlation coefficient, and multiplexing efficiency are studied in the user proximity. The optimized structure is fabricated and measured. The measured S-parameters cover WLAN (2.46-2.6 GHz), WiMAX (3.37-3.75 GHz), and HIPERLAN (5.2-5.87 GHz) based on −10 dB reflection coefficient and −24 dB isolation is achieved between antenna ports. Good agreement is obtained between the simulated and measured results. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:510-521, 2015. [ABSTRACT FROM AUTHOR]

A planar compact multiband monopole antenna is presented for ultra-slim mobile handset applications. The proposed antenna operates over 0.885 GHz-0.962 GHz and 1.69 GHz-3.8GHz frequency bands with -6 dB impedance bandwidth that covers GSM900, GSM1800, GSM1900, UMTS, IMT2100, WLAN, WiMAX along with most of the higher LTE bands of modern mobile phone applications. The radiation characteristics of the antenna is analyzed in term of radiation patterns, peak realized gain, total radiation efficiency, and surface current distribution. The radiation patterns of the proposed antenna are dipole like which is suitable for mobile applications with 73-93% total radiation efficiency. The proposed antenna is investigated in free space as well as in actual mobile environment consisting of mobile plastic housing along with large metallic display screen and battery. No significant effect on the operating bands of the mobile antenna due to the actual mobile environment on the impedance bandwidth is observed. Specific absorption rate (SAR) computation is carried out on human head phantom. The computed values of SAR lie well below the specified limit over 1 g and 10 g of tissues. The parametric analysis is also carried out to understand the effect of the shape parameters. [ABSTRACT FROM AUTHOR]

The theoretical and experimental investigations carried out on a gap-coupled microstrip array antenna reveal that there is a significant improvement in VSWR and bandwidth characteristics of the gap-coupled microstrip array antenna as compared with a conventional microstrip array antenna. The input impedance and the resonant frequency of the gap-coupled patch are found to depend heavily on the gap length as well as on the dielectric constant of the substrate material. [ABSTRACT FROM AUTHOR]

A small size, planar and co‐planar waveguide fed metamaterial inspired antenna is proposed for ultra‐wideband (UWB) application. The main radiating element consists of three split‐ring resonators (SRR) and placed along one axis. Moreover, coplanar waveguide (CPW)‐fed line along with modified ground plane is used to improve the impedance matching. The physical size of proposed antenna is 25(W) × 22 (L) × 1.6 (H) mm3. The CPW‐fed metamaterial inspired antenna provides bandwidth of 10.4 GHz from 3.1 to 13.5 GHz based on the 3:1 (voltage standing wave ratio [VSWR] <2). Over the range of UWB frequency, peak realized gain varies from 2.5 to 4 dBi. The proposed antenna provides omnidrectional radiation patterns. Further, fidelity factor of the proposed antenna is also calculated and measured. The calculated fidelity factor is suitable for UWB applications. Finally, prototype of the antenna is developed and tested using network analyzer. The simulated and measured results are in good agreement. [ABSTRACT FROM AUTHOR]

Abstract An integrated design of compact filtering antenna having high selectivity and suppressed unwanted harmonics is proposed in this paper. The proposed filtering antenna is obtained by integrating a modified elliptic-shaped monopole antenna with a modified interdigital bandpass filter (IBPF). At first, a modified elliptic-shaped monopole antenna is designed and investigated through numerical simulation and experimentally. Further, the modified IBPF reported in the literature is integrated with the proposed monopole antenna to achieve good passband selectivity and suppressed unwanted harmonics for the proposed filtering antenna. The proposed filtering antenna is analysed through numerical simulation software. The simulated −10 dB reflection coefficient bandwidth of the proposed filtering antenna covers the frequency range 1.01–1.96 GHz with improved band-edge selectivity and unwanted harmonic suppression up to 8 GHz (= 5.4 f 0 , where f 0 is the centre frequency of passband). It has nearly stable omnidirectional radiation patterns over the whole frequency band. The proposed filtering antenna was fabricated and experimentally tested. The experimental results are nearly in agreement with corresponding numerical simulation results. The proposed filtering antenna can be a suitable candidate for various L-band wireless communication applications. [ABSTRACT FROM AUTHOR]

A compact eight-element MIMO antenna for wideband applications with dual-band sharply dispensation characteristics is presented. A same oriented two-element antenna is placed in orthogonal symmetric fashion on an octagon-shaped substrate cross-section area of 0.4374 λ 0 2 (at 3.03 GHz), forms an eight-element MIMO antenna. A combination of stubs between same oriented elements and dual I-shaped stubs between a pair of corner elements are used to the interconnected ground for high isolation. The proposed MIMO antenna achieved a −10 dB measured fractional bandwidth (S ij ∈ i = j) of 133.98% (3.03–15.33 GHz) and obtained a minimum isolation value (S ij ∈ i ≠ j) of 15.5 dB. The dual quarter-wavelength slits are created in each radiator for dual notched-bands at 5.1–5.8 GHz and 6.7–7.3 GHz. The measured and simulated results are found in good agreement. [ABSTRACT FROM AUTHOR]

A single-layer, low-profile beam scanning reflectarray (RA) fed by a spoof surface plasmon polaritons (SSPPs) based endfire MIMO antenna is proposed in this manuscript. The RA is based on a variable elliptical-shaped unit cell designed at 10.4 GHz. The unit cell has a low insertion loss of 2.3 dB and a reflection phase of 315.2°in the working frequency band from 9.52–11.23 GHz. The SSPPs based endfire MIMO antenna is used to mitigate the aperture blockage, achieve high isolation between the feed elements, and accomplish the continuous one-dimensional (1-D) beam scanning of ± 8°from the broadside. The maximum realized gain of the proposed reflectarray in the broadside direction is 22.6 dBi with a 3-dB beamwidth of 5.7°. The minimal beam switching loss is in the other direction, and the realized gain is 22.4 dBi with a 3-dB beamwidth of 5.8°. The 3-dB gain bandwidth (GBW) of 9.7 % of the proposed RA benefits nano-satellite applications. The fabricated prototype measurements in an anechoic chamber environment verify the simulated results. [ABSTRACT FROM AUTHOR]

This work proposes a three-port, low-profile, coplanar endfire multiple-input-multiple-output (MIMO) antenna based on spoof surface plasmon polaritons (SSPPs). The proposed antenna comprises a coplanar waveguide (CPW)-fed SSPPs transmission line (TL). A transition to transform the CPW quasi-TEM mode to the SSPPs mode. The radiator section with asymmetric discontinuities converts the bounded SSPPs waves into radiating waves. The proposed MIMO antenna exploits the inherent feature of high isolation in the SSPPs TL due to its strong field confinement competency. Wider beamwidths for ample azimuth and elevation coverage with a stable pattern in the endfire direction are achieved in the 9.52–11.23 GHz operating band. In the operating band, the MIMO antenna has an average realized gain of 6 dBi. Mainly, it has high isolation below -35 dB (measured) in the operating range, a maximum envelope correlation coefficient (ECC) of 1.5 × 10−3, and a total active reflection coefficient (TARC) value below 0.3. The measured results are closely matched with the simulated ones in terms of S-parameters, radiation pattern, ECC, TARC, and CCL. [ABSTRACT FROM AUTHOR]

In this paper, we present a dual wide-band ingestible antenna design for wireless capsule endoscopy (WCE) biotelemetry applications. The design process employs Characteristic Mode Analysis (CMA) and driven modal analysis. The effectiveness of the prototype antenna is afterward assessed through measurements using a tissue-equivalent phantom liquid model. We investigate the effects of antenna implantation depth and capsule shell thickness on its performance, providing insights into practical considerations. The proposed dual-band antenna demonstrates good performance in both the 1.4 GHz Wireless Medical Telemetry Services (WMTS) and 2.45 GHz Industrial, Scientific, and Medical (ISM) bands, exhibiting measured impedance bandwidths of 36% and 22%, respectively. The measured peak realized gains are −22.9 dBi and −25.3 dBi for the WMTS and ISM bands, respectively, with a compact footprint of 78.5 mm2. To ensure health and safety and optimal performance, we evaluate the antenna's specific absorption rate (SAR) and link margin (LM). Additionally, we assess the performance of the proposed antenna in comparison with the state-of-the-art design for capsule antennas in WCE applications. [ABSTRACT FROM AUTHOR]

This paper presents the design of a compact ultra-wideband (UWB) antenna and a frequency reconfigurable antenna with high isolation for cognitive radio (CR) applications. The antenna prototype comprises a UWB antenna for sensing UWB spectrum and a frequency reconfigurable antenna for communication purposes. The proposed antenna has been designed on FR-4 substrate with a compact size of 25 × 36 × 1.6 mm3 (0.22λ 0 × 0.32 λ 0 × 0.014λ 0) , where λ 0 is free space wavelength at 2.7 GHz. The −10 dB impedance bandwidth is realized for UWB antenna ranges from 2.7 GHz to 10 GHz and for frequency reconfigurable antenna in two frequency bands from 4.3 GHz to 5.5 GHz and 5.1 GHz to 6.8 GHz. A T-shaped stub is integrated into the ground plane to achieve high isolation between antenna element ports and the impedance bandwidth improvement. The proposed design attains high isolation of −21 dB over communication frequency range of frequency reconfigurable antenna and most of the UWB spectrum. The prototype has been fabricated and measured. The measurement results are in good agreement with the simulated results. [ABSTRACT FROM AUTHOR]