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This paper introduces a novel design concept for a compact sub-6 GHz four-port flexible antenna tailored specifically for 5G applications. The antenna utilizes a coplanar waveguide (CPW) architecture featuring a moon-shaped radiating element, implemented on a flexible Felt substrate with a dielectric constant of 1.2. Operating within the 3.4 to 3.8 GHz spectrum, the antenna underwent fabrication and rigorous measurement. Remarkably, the measured results closely matched the simulated outcomes, validating the design's accuracy. Furthermore, various MIMO parameters such as envelop correlation coefficient (ECC), total active reflection coefficient (TARC), channel capacity loss (CCL), diversity gain (DG), and mean effective gain (MEG) were computed, providing comprehensive insights into the antenna's performance metrics. An analysis of the antenna's conformability confirms its suitability for integration across diverse 5G applications. Overall, the findings demonstrate that the proposed antenna exhibits promising characteristics, making it an ideal candidate to meet the evolving demands of 5G communication systems. [ABSTRACT FROM AUTHOR]

This paper presents a complementary split-ring resonator (CSRR) loaded coplanar waveguide (CPW) fed with a circular shape, miniaturized diamond slot planar monopole antenna. The proposed antenna for healthcare monitoring biomedical applications uses the industrial medical and scientific band. The antenna design and development to implant the human phantom are proposed. The primary goal of this work is to continuously monitor the patient's ability to detect abnormal conditions as soon as possible as a result of improvements in quality of life. In this case, an antenna design methodology must prioritize features such as miniaturization, increased gain and bandwidth, and biocompatibility. Simulated and measured antenna characteristics for biomedical applications are performed at ISM Band frequency. [ABSTRACT FROM AUTHOR]

In order to solve the problem of decreasing transmission efficiency due to impedance abrupt change during the cascade between transmission line and chip, a matching band-line method for X~Ka band was proposed based on the ground coplanar waveguide and chip cascade structure. The input impedance of the chip was extracted by S parameter, and the impedance discontinuities in the RF circuit were analyzed. The impedance matching circuit was designed and the 3D simulation model was established. Through finite element simulation, the influence of matching circuit and bonding lead center distance on RF transmission performance was discussed, and the transmission performance difference of different structures and matching circuits was compared and analyzed. The simulation results show that the matching circuit can make S11-0.19 dB of the grounded coplanar waveguide and chip cascade structure in the X~Ka band. The optimized grounded coplanar waveguide and chip cascade structure can significantly improve the isolation of RF signal and reduce channel crosstalk while reducing transmission loss, which provides theoretical reference for the design of RF circuits in the centimeter-wave band.

Satellite communication has reached a turning point in transmitting data quickly and receiving signals clearly in faraway places. This paper presents a metamaterial-based antenna for distant and military applications that overcomes restrictions and performs unmatched. This project explores metamaterials to create a unique antenna. Expect to be astounded by its power to bend electromagnetic waves, miniaturize, and change our relationship with the universe. The feeding mechanism of this antenna is a modified co-planar waveguide. At 5.6 GHz, the proposed antenna unit cell measures 0.076λ0×0.2λ0, making it small thanks to its MTM characteristic. CP radiation is made when two orthogonally polarized modes are stimulated at the same time and two composite right- and left-handed transmission line unit cells are placed orthogonally. Reduced size, increased bandwidth, and improved Learn how this discovery opens new doors for high-resolution photography, broadband internet, and space exploration. One nanostructure that makes up a metamaterial is the Split Ring Resonator (SRR). SRR dimensions must be smaller than the resonance wavelength, making them crucial for near-infrared and optical responses. This effort examined nanoscale SRR characteristics in the infrared and visible ranges. SRRs composed of aluminum (Al) and gold (Au) were produced on silicon and silica substrates using electron beam lithography (EBL). The proposed structure consists of a microstrip-line-supplied SRR, a parasitic patch that is perpendicular to the ground plane, and two via holes connected by two split rings that feed the patch indirectly. Choosing the right material parameter for all such antennas depends on the planned structure. Fabrication and testing of the antenna matched simulations. Dimensions: 23.7 mm × 16.2 mm × 1.6 mm; substrate dielectric constant: 4.4. Experimental data are detailed and compared to analytical calculations. Simulation results show that metamaterials have negative permittivity and permeability in a certain frequency range, which can be predicted by an analytical method. Simulations indicated eight BRS, WiMAX, radar, and mobile phone resonance frequencies. Radiation is dipole-like in the omnidirectional in the H-plane and E-plane. 10 dB return loss and 3 dB axial ratio bandwidths are 38.6.7% and 8.1%, respectively.

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In modern communication systems, ultra-wideband (UWB) technology has garnered substantial attention due to its superior attributes compared to traditional narrowband communication systems. Over the past decade, UWB technology has also found applications in microwave-based imaging systems. This study introduces a simple planar coplanar waveguide-fed circular shape arc slot antenna designed specifically for biomedicine and microwave medical imaging applications. The proposed design is implemented on a 1.6-mm-thick FR4 substrate with a relative permittivity of 4.4 and a loss tangent of 0.0009. The antenna has physical dimensions of 26 mm × 29 mm and achieves an impressive bandwidth of 16.6 GHz, spanning 2.4 to 19 GHz. It exhibits a peak gain of 2.5 dBi and consistent omnidirectional radiation characteristics. Thorough temporal analysis validates the antenna's performance within acceptable limits, which is further affirmed through practical fabrication and testing, demonstrating strong agreement with simulation results. [ABSTRACT FROM AUTHOR]

This communication presents a wideband and a low-profile flexible wearable antenna intended to operate at a 2.45 GHz WBAN band. The suggested antenna comprises a CPW-fed monopole antenna backed by an artificial magnetic conductor (AMC) to act as a reflector. The latest AMC-integrated design uses R03003 as a dielectric substrate. The suggested design features an impedance bandwidth of 71.03% (1.87–3.93 GHz) with a gain value of 3.62 dBi and has a compact footprint of 40 × 40 mm2. The incorporation of wideband AMC with a monopole antenna leads to bandwidth enhancement and covers the 3.5 GHz WiMAX band. Simulation and experimental studies provide evidence that in the case of structural deformities and human body loading, the suggested AMC-integrated antenna is stable and shows superior efficiency relative to the traditional monopole antenna. Furthermore, numerical analysis demonstrates that the amount of radiation AMC-integrated antenna decreases tremendously in terms of specific absorption rate for various bodily attachment scenarios. Three body templates with various compositions and forms were used to study the effects of the antenna on bodily attachment. Extensive experiments on human body phantoms and bodily attachment are also conducted and the results are presented. The suggested AMC-integrated design thus confirms a promising contender for portable wearable wireless applications. [ABSTRACT FROM AUTHOR]

This study introduces a coplanar waveguide MIMO antenna design that offers both frequency and pattern reconfigurability. The antenna is intended for applications in WiMAX, WLAN, and X-Band. It is constructed using an FR4 substrate with dimensions of 1.6mm thickness and 0.025 loss tangent. Based on the proposed design, MIMO antennas can operate at 3.5 & 3.9GHz (WiMAX), 5.5 & 5.8GHz (WLAN) and 10.5 & 12.5GHz (X-Band). To accomplish this, two open-circuited 3mm x 3mm quatre wavelength transformers are linked to each radiator through PIN diodes. The performance enhancement of the reconfigurable MIMO antenna was fine-tuned utilizing microwave solvers in both CST and ADS. The system’s performance was validated through practical measurements. Furthermore, the analysis of diversity conducted on the suggested antenna reveals that the antenna has a low correlation coefficient (

Wireless communication technology evolves to meet current needs, focusing on antenna size reduction for smaller, multi-frequency devices. This research introduces a novel approach to miniaturizing a multiband Electromagnetic Band Gap (EBG) reflector using a Double Interdigitated Coplanar Waveguide (DICPW) structure. The mushroom-patterned EBG unit cell, employing a double interdigital technique based on a Coplanar Waveguide (CPW), achieves a significantly slower wave on the transmission line. The unit cell size can be reduced from $\lambda $ /2 to $\lambda $ /8, allowing control over the second to fourth resonance frequencies. Engineered for a fundamental frequency of 1.8 GHz (LTE), the proposed EBG unit cell supports frequency ranges of 2.45 GHz (WLAN), 4.3 GHz (Altimeter), and 5.2 GHz (WLAN). Integrating this EBG reflector with a dipole antenna at the same frequency results in directional radiation patterns and gains of 8.29 dBi, 8.76 dBi, 8.55 dBi, and 8.22 dBi at resonance frequencies. The innovative reflector, with improved gain and compact dimensions, is relevant to cube satellite and wireless communication systems with versatile multiband frequency requirements.

An antenna design with a coplanar waveguide (CPW) fed wide band circular polarization (CP), inspired by compact metamaterials, is presented in this paper. Substrate Integrated waveguide (SIW), metamaterial with CPW feed, and monopole patch make up its construction. A three-GHz axial ratio bandwidth (ARBW) is obtained by adding a rectangular slot at the monopole stub to produce CP. Incorporating SIW and metamaterial into the antenna design improves gain, directivity, bandwidth, and efficiency. Metamaterial and SIW utilized in the design comprising monopole patch with a stub, slots at the edges and the stub improve the antenna properties efficiently. ISM band, WLAN, and WBAN applications are appropriate for the suggested antenna. The antenna has a 3.6 dBi gain and measures 20 × 20 × 0.8 mm3. A radiation efficiency of 98% and a fractional bandwidth of 63.9% are obtained by incorporating the advantages of CP in a broadband SIW antenna inspired by metamaterials (3.99–7.62 GHz). [ABSTRACT FROM AUTHOR]

In this letter, a novel dual‐band bandpass filter (BPF) with independently controllable center frequencies, bandwidths, and transmission zeros (TZs) is presented. The proposed BPF is realized by using eighth‐mode substrate‐integrated circular cavities (EMSICCs) and coplanar waveguide (CPW) resonators. The CPW resonators are embedded in the upper surface of the EMSICCs, allowing for a compact size without additional circuit dimensions. Finally, a dual‐band BPF for WLAN is designed and fabricated with center frequencies of 2.45 and 5.2 GHz. The measured results closely align with the simulated ones, validating the performance of the filter. Multiple TZs are generated by cross‐coupling and source‐load coupling, which results in good out‐of‐band rejection performance. [ABSTRACT FROM AUTHOR]

A Novel design of a curved single‐layered frequency selective surface with an 11 × 11 array of a 13 × 13 mm‐sized unit cell has been merged with a miniaturized, CPW‐fed ultra‐wideband monopole of dimensions (20 × 25 mm2) for gain enhancement. The suggested prototype, crafted on an FR‐4 dielectric substrate and demonstrates a very broad bandwidth starting from 2.66 to 17.98 GHz (148%), which covers the entire UWB frequency band. The combined antenna‐curved FSS reflector shows a very important gain improvement from 0.2–5.4 dB to 8.8–14.9 dB, having a peak gain increase of 10 dB at 10.6 GHz. Basic design features were studied and discussed through simulations, yielding promising results The proposed structure can be used in UWB and GPR applications. [ABSTRACT FROM AUTHOR]

We investigate the time domain characterization of a coplanar waveguide (CPW) based on an on-chip electro-optic sampling (EOS) system for millimeter waveform metrology. The CPW is fabricated on a thin layer of low-temperature gallium arsenide (LT-GaAs), and the substrate material is GaAs. A femtosecond laser generates and detects ultrashort pulses on the CPW. The forward propagating pulses are simulated using a simplified current source for the femtosecond laser at different positions on the CPW for the first time. Then, the influences of the CPW geometry parameters on the measured pulses are discussed. The varying slot width has larger influences on the amplitude of millimeter wave pulses than the center conductor width and the pumping gap. Finally, in the frequency range of 10 GHz to 500 GHz, the transfer functions calculated by the time domain pulses are in good agreement with the transfer functions calculated by the frequency domain ports. The above results are important for improving the measurement precision of the millimeter waveform on the CPW for millimeter waveform metrology. [ABSTRACT FROM AUTHOR]

To achieve better accuracy in their investigations, biologists have recently been using three-dimensional models as intermediates between two-dimensional cell culture and the in vivo study of tissues. Some of these models are based on spheroids, which are cellular aggregates retaining many characteristics of in vivo behaviors while being still easy to use and implement in labs. To study such objects, multiple observation techniques can be used according to the objective of the study, including those using electromagnetic waves as nondestructive, noninvasive, and label-free analysis. Low-frequency (<1 MHz) ones are currently under investigation as electrochemical impedance spectroscopy. However, unlike microwaves (from 300 MHz to 60 GHz), they cannot penetrate the cell. Furthermore, most of the devices dedicated to microwave dielectric characterization are only focusing on cellular scales lower than spheroids (single cell, cell mats, or suspensions) or on tissues and organs. In this article, a microwave spectroscopy device using a coplanar waveguide adapted to the study of spheroids is presented with the dielectric characterization of fixed spheroids, with capacitance and conductance measurements from 0.5 to 20 GHz, aiming at filling the scale gap in the state of the art. [ABSTRACT FROM AUTHOR]

Antenna selection is a decision-making problem involving multiple factors, some of which may be at odds. This study aimed to develop a model for optimizing the design process for GSM mobile phone antennas. A 3.5GHz and 5.5GHz onchip circularly polarized (C.P.) artificial magnetic conductor (AMC) based Vshaped stepped multiband 25x25mm2 antenna has been designed and fabricated. The proposed antenna's profile height is much lower than antennas supported by traditional perfect electric conductor (PEC) ground planes due to careful tuning of the AMC reflector's reflection properties through optimization technique. According to simulated and observed data, the antenna presented in the proposal has the potential to achieve an impedance bandwidth of more than 45% (VSWR less than 1.8) while maintaining consistent radiation patterns across the frequency ranges 3.4 GHz to 5.86 GHz, 10.28 GHz to 11.86 GHz, and 13.69 GHz to 14.69 GHz. Measured analysis includes gain, radiation pattern, Axial Ratio, and return loss(S11). The proposed antenna can be recommended for use in micro base station systems is suitable for this application because it possesses a low profile structure, an advantageously broad bandwidth, and the ease with which it can be manufactured. [ABSTRACT FROM AUTHOR]

Liquid crystals have already been widely used in reconfigurable microwave devices through external electrically controlled dielectric properties. The traditional method is to sandwich liquid crystals between two metal layers etched on hard substrates. However, this method of adding external electric fields tends to cause short-circuiting between the upper and lower electrodes of liquid crystals in the bending state for the case of electrodes on flexible substrates. In this paper, a novel method is proposed to realise a frequency tunable resonator using liquid crystal fabricated on flexible substrates. The resonator is composed of coplanar waveguide structures. Since the metal layers of the coplanar waveguide placed on the same horizontal plane do not touch each other when bending, it allows the controlled electric field direction to be parallel to the electrode layers. Liquid crystals are placed under the coplanar metals for the electric field control. In order to maximise tunability, the structural parameters of the proposed structure were analysed in detail. The test results agree with the theory and simulation to verify the reliability of this frequency tunable resonator. Furthermore, the test results also illustrate that the applied electric field method can achieve the frequency continuous electrically tunable function when the flexible resonator is bending. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract—An experimental method was developed to determine losses in microstrip and coplanar transmission lines for devices operating in the frequency range of 77–81 GHz. The parameters of the scattering matrices are obtained using a vector network analyzer and frequency upconverters. The calculation of losses in waveguide-coplanar and coplanar-microstrip adapters is made. [ABSTRACT FROM AUTHOR]

This paper proposes a spoof surface plasmon polariton (SSPP) low-pass filter by etching butterfly-shaped cells on the middle line of a coplanar waveguide (CPW). The transmission and dispersion characteristics of the structure are analyzed. This design has a perfect low-pass transmission with tunable cutoff frequency. The angle and radius of the butterfly grooves are two variables that can adjust the cutoff frequency. The existence of two parameters is helpful to design a constant-width transition between the CPW and CPW-SSPP structures. It can be obtained by varying the angle of the butterfly grooves, while their radius is fixed. The introduced butterfly SSPP achieves a cutoff frequency reduction of 33% in comparison with its conventional rectangular counterpart with the same lateral size. It also has less phase velocity and more slow-wave effects than the rectangular SSPPs. Consequently, both transverse and longitudinal dimensions can be reduced by using the butterfly grooves. Moreover, the transition length is significantly reduced. The measured results show a 3-dB bandwidth from 0 to 10 GHz, a return loss of greater than 13.76 dB, an insertion loss of less than 1.6 dB, and an out-of-band rejection of higher than 15 dB from 10.2 to 14.5 GHz. The proposed circuit with the compact size, low loss, groundless structure, excellent slow-wave effect, and compact transition with excellent mode conversion can be applicable to the future communication systems. [ABSTRACT FROM AUTHOR]

In this paper, we propose a comparative method to analyze a complex microwave structure consisting of a silicon-based coplanar waveguide line and four electric-LC resonators, thus forming a wideband microwave band-stop filter that can be easily integrated at the wafer level together with other devices and sub-systems for large-scale production of high-frequency electronics. A rigorous and careful approach is needed when choosing the proper simulation settings and, as a good rule of thumb, both time and frequency domains should provide the same results. Furthermore, the experimental validation requires supplementary components (like connectors), often ignored when designing an electromagnetic structure highly impacting on the overall performance. In this work, we go in depth into all these issues and show how the right choices in terms of computational parameters can lead to a good agreement with the measurements of the proposed CMOS-compatible band-stop filter in the band 2–18 GHz, with a relative bandwidth of almost 30 % around the band-stop frequency of 13.2 GHz and a rejection level of − 40 dB. [ABSTRACT FROM AUTHOR]

Summary: A hexagonal shaped circularly polarized (CP) wideband slot antenna using multiple stubs has been proposed and investigated. A hexagonal slot is created in the ground plane with tapered sections improving the impedance matching. Two radiators are incorporated in the structure, which is responsible for generating orthogonal degenerate modes; hence, CP radiation is achieved for the proposed antenna. For enhancing the gain of antenna, one radiator is directly connected to feed line and another one embedded in the ground plane. An inverted L‐shaped arm is inserted in the slot to enhance and tune the circular polarized behavior. The presented radiator have input reflection coefficient ranges from 5.67 to 8.50 GHz (39.97%) and axial ratio bandwidth (ARBW) of 5.60–8.50 GHz (41.13%). The proposed antenna provides overlapping bandwidths of 5.67–8.50 GHz (39.97%) having average gains of 5.25 dBi within the entire frequency bands. The presented antenna is exceptionally good for the application of mobile and satellite communications. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The growing interest in the modulation of phase (and amplitude) of microwave and millimeter-wave signals has been spurred by the emerging 5G/6G phased-array beam-steering applications for which liquid crystal is one of the enabling technologies. A problematic journal paper on liquid crystals-based coplanar waveguide phase shifters is scrutinized in this letter to urge readers and a wider academic community's attention. Specifically, concerns have come up about the usefulness, effectiveness, and accuracy of the simulation-only work that Jun-Seok Ma et al published recently at J. Phys. D: Appl. Phys. 55 095106, entitled 'liquid-crystal-based floating-electrode-free coplanar waveguide phase shifter with an additional liquid-crystal layer for 28 GHz applications'. With no devices fabricated and no experimental measurements, the simulation results and conclusions are subject to fundamental yet important errors (significant overestimations) that can mislead readers as well as researchers truly working in the field of liquid crystals-based tunable microwave and millimetre-wave devices. The lack of experimental data means that the validity and reliability of the simulation results cannot be fully assessed. A reflection on other drawbacks of the article is also elaborated in this letter. [ABSTRACT FROM AUTHOR]

This paper presents a dual-mode characteristic for miniaturized metamaterial with a unit cell design based on an interdigital coplanar waveguide (ICPW) combined with trisection step-impedance to enable the three resonant frequency responses of 1.8 GHz, 3.7 GHz, and 5.8 Hz. In addition, the unit cell dimensions can be reduced from $\lambda $ /2 to $\lambda $ /8 due to the fact that the ICPW technique based on the CPW structure enhances the capacitive load between the transmission line and the side ground, thereby increasing the slow-wave on the transmission line. In addition, the trisection step- impedance will be incorporated and applied to the transmission line and cooperate with the unit cell structure’s capacitive load to effectively resonate at the desired frequency location. Moreover, the unit cell structure designed with the method above must be utilized as a double layer in which the structure on both sides is identical. The back structure will property the rod, which will cause the permittivity and permeability to be negative and closer to zero. This property of the proposed material allows for its utilization as a director at its first resonant frequency and as a reflector at the subsequent second and third resonant frequencies. The proposed metamaterial employs FR-4 printed circuit boards with a dielectric constant ( $\varepsilon _{r}$ ) of 4.4, a substrate thickness of 1.6 mm, a conductor thickness of 0.035 mm, and a loss tangent (tan $\delta $ ) of 0.04. The unit cell size is approximately 14 mm $\times 14$ mm. The unit cell will then be arranged as a $7\times 7$ array with an overall dimension of $98\times 98$ mm2 to evaluate an antenna’s performance. An antenna used for testing the proposed unit cell is a dipole antenna that propagates at a single frequency corresponding to the unit cell’s resonant frequency. At all resonant frequencies, the impedance matching of the dipole is less than −10 dB. At 1.8 GHz, 3.7 GHz, and 5.8 GHz, the dipole antenna gain is 2 dBi, 2.06 dBi, and 1.95 dBi, respectively. Moreover, the dipole antenna’s characteristics were simulated using the CST program in conjunction with the unit cell array. Based on the simulation and measurement results, the antenna with the unit cell array exhibits an impedance bandwidth of less than −10 dB at frequencies of 1.8, 3.7, and 5.8 GHz. The gains obtained from the simulation results are 5.49 dBi, 8.21 dBi, and 7.87 dBi, while the measurement results show gains of 5.73 dBi, 8.19 dBi, and 7.79 dBi, respectively. The simulated and measured outcomes demonstrate a substantial correspondence.

This paper presents a multiband director based on the frequency selective surface (FSS) unit cell structure using the double layer with interdigital CPW (ICPW) technique. The unit cell consists of the front and the back. The front part has been designed using an ICPW technique based on a coplanar waveguide structure to enhance the capacitance between the transmission line and the semi-ground. The overall structural dimension of the unit cell can be designed to be smaller than the conventional range of $\lambda $ /2 to $\lambda $ /8, due to the influence of the slow wave effect on the capacitance of the structure. The back part is the inverted layer of the front, which alternates between substrate and copper. It is composed of a square loop resonator with a double meandering line. The capacitance generated by a double meander line enhances the capacitance in the front part, which influences the control of all resonant frequencies and increases the slow wave on the double-layer unit cell structure, resulting in a significantly reduced dimension. The resonance frequencies for the designs are 1.8 GHz (LTE), 3.7 GHz (Wi-MAX) and 5.2 GHz (WLAN), respectively. According to simulation results, the FSS can transmit all resonant frequencies. It has an overall dimension of 10.93 mm $\times11.48$ mm. In addition, the FSS unit cell has been arranged as a $7\times 7$ array for use as a director. The dimensions are 73.48 mm $\times77.38$ mm. The FSS director will be evaluated utilizing an omnidirectional dipole antenna at the same resonant frequency as the FSS unit cell. According to both the simulated and measured outcomes, the impedance matching value is below -10 dB at the three resonant frequencies. The FSS director equipped with a dipole antenna exhibits bidirectional propagation characteristics across all resonant frequencies. The antenna gains for simulation are 3.45 dBi, 3.05 dBi, and 3.72 dBi, while the antenna gains for measurement are 3.05 dBi, 2.98 dBi, and 3.12 dBi. The findings indicate a high level of concurrence.

In recent years, advances in material science for high-frequency electronics have generated novel materials that offer superior performance. Additive manufacturing (AM) has expanded the frontiers of microwave material manufacturing going beyond flat geometries and unique properties such as graded permittivity materials. Accurate electromagnetic (EM) material characterization for AM materials remains challenging given the printing volume constraints for manufacturing processes, as traditional EM property extraction techniques often require electrically large samples. Furthermore, loss extraction techniques typically cannot differentiate dielectric and conductor losses in waveguides. This paper presents a novel conformal mapping-based characterization technique using coplanar waveguides (CPW) with air pockets that allows for dielectric permittivity and dielectric loss extraction. The underlying principle of the techniques is to use a set of CPWs with different air slot depths to extract the loss behavior as a function of the slot depth. A new loss-slot rate metric is introduced to decouple the dielectric and conductor losses in the structure. The theoretical foundation of the technique is used to develop a physical-mathematical model for dielectric property extraction that is verified with simulations and experiments for materials with permittivity in the range 2.33–29, and loss tangents of 0.02–0.055. The average error for the equivalent capacitance of the CPW with air pockets (CPW-AP) between the presented model and simulated or measured data is 2.4% for all the studied cases. The experimental confirmation is performed with traditionally manufactured FR-4 and additively manufactured yttria-stabilized zirconia (YSZ) dielectrics up to 10 GHz.

In this article, a narrow-band rejection plasmonic filter based on spoof surface plasmons polariton is reported. The structure is composed of a coplanar waveguide constructed with two defects at the bottom, periodic arc branches and metal strips. Varying the radian of the arc branch controls the frequency range of the filter's narrow band and the change of metal strip height enhances the rejection ability of filter. The filter is simulated and fabricated. Its simulation daters are consistent with the experimental daters. The proposed rejection filter exhibits a strong stopband in 4.8–5.0 GHz, whose transmission coefficient is less than − 35 dB in simulation. In the passband, the transmission loss is around 1 dB. It is hoped that this filter may have better application prospect in integrated circuits and microwave communication devices. [ABSTRACT FROM AUTHOR]

In recent years, there has been a development of multifunctional components, including filtering antennas. Co-designing the filter and antenna can effectively reduce the overall size and thus realize high integration. A new coplanar waveguide (CPW) omnidirectional filtering antenna with a pair of gain zeros is presented using separation electric/magnetic coupling (SEMC) paths that greatly enhance frequency selectivity and effectively suppress the spurious responses of the circular patch radiator. The impedance bandwidth of the filtering antenna can also be controlled/adjusted through electric/magnetic coupling. The design results demonstrate that the filtering antenna achieves an omnidirectional pattern with a center frequency of 3.7 GHz, an impedance bandwidth of about 3%, a gain of 2.7 dBi, and a pair of gain zeros. [ABSTRACT FROM AUTHOR]

The Gap Waveguide technology utilizes an Artificial Magnetic Conductor (AMC) to prevent the propagation of electromagnetic (EM) waves under certain conditions, resulting in various gap waveguide configurations. In this study, a novel combination of Gap Waveguide technology and the traditional coplanar waveguide (CPW) transmission line is introduced, analyzed, and demonstrated experimentally for the first time. This new line is referred to as GapCPW. Closed-form expressions for its characteristic impedance and effective permittivity are derived using traditional conformal mapping techniques. Eigenmode simulations using finite-element analysis are then performed to assess its low dispersion and loss characteristics. The proposed line demonstrates an effective suppression of the substrate modes in fractional bandwidths up to 90%. In addition, simulations show that a reduction of up to 20% of the dielectric loss can be achieved with respect to the traditional CPW. These features depend on the dimensions of the line. The paper concludes with the fabrication of a prototype and validation of the simulation results in the W band (75–110 GHz). [ABSTRACT FROM AUTHOR]

A novel highly miniaturized triple band structure based on Z‐slots‐shaped antenna is presented in this letter, with only 0.0015 λ02 ${{\rm{\lambda }}}_{0}^{2}$ footprint, where λ0 ${{\rm{\lambda }}}_{0}$ is the free space wavelength at 1.3 GHz. The proposed design can generates three resonant frequency bands (1.3–1.62 GHz), (2.22–2.59 GHz), and (3.24–3.65 GHz) with −10 dB reflection coefficient, a triple band function is achieved by etching tow connected Z‐shaped‐slots in the radiating element and the differential evolution algorithm is then used to control the currents path, the prototype of the proposed antenna is printed on a single substrate layer and fed via coplanar waveguide CPW technology. The measured and simulated results are in good agreement, and validate the design principle, the results show that the antenna has a compact size (19.5 × 17.6 mm2), aside from its planar design, simple manufacturing, and low cost to fabricate, this antenna exhibits stable omnidirectional radiation patterns in E plane as well as bidirectional radiation patterns in H plane, making it an ideal device for multiband applications. [ABSTRACT FROM AUTHOR]

A differentially fed dual-polarization slotted antenna with an ultra-wide bandwidth and low cross polarization is presented in this paper. The antenna is composed of a radiation patch and a ground plane, both of which are printed on the top of the dielectric substrate. The ground is extended toward the radiation patch to form a slotted coplanar structure. In order to expand the bandwidth, a cross-shape symmetrical slotted structure is loaded into the radiation patch. Differential feed is adopted to realize 0°C/90°C linear polarizations and suppress the cross polarization. Simulation and measurement results show that the proposed antenna with dimensions of 0.53λC0 × 0.53λ0 × 0.0135λ0 (λ0 is the wavelength at 4 GHz) has a differential mode impedance bandwidth of 82.25% (2.27-5.56 GHz), a differential feed port isolation of higher than 28 dB, and a cross polarization level of less than -30 dB, which achieves the characteristics of ultra-wideband, high isolation, and low cross polarization level. [ABSTRACT FROM AUTHOR]

This paper presents a compact tri-band antenna with double winding structures for 3G/4G/5G base station applications. The proposed compact tri-band antenna design with double winding structure fed by a coplanar waveguide (CPW) reduces the installation space and mutual coupling between close frequency operation bands suitable for base band applications. The proposed antenna design can be configured for step-up and step-down transformer operation using double winding structures on either side of the central resonator with an ability to attain reversibility of transformer operation. The proposed compact tri-band antenna performance is evaluated for both with and without windings in the antenna structure. The proposed design without the winding structure achieves a dual band of operation whereas the design with a winding structure achieves tri-band operation with improved S11 performance and very less voltage standing wave ratio (VSWR). Two prototypes of tri-band ultra-wideband (UWB) antenna with double winding structures of high design specifications are fabricated and tested to validate the proposed design principle. The effectiveness of the projected design is evident from the excellent association between simulated and measured results. It is shown that the proposed design is very effective with low cost and the fabricated prototypes of the antenna with double winding structures are very compact with the dimensions of 18.6 X 15.6 mm2 achieving three frequency bands of operations at 2.9 GHz, 6.5 GHz, and 11.3 GHz with improved return loss < -10db and VSWR < 1.8. [ABSTRACT FROM AUTHOR]

This article aims to examine the |S11| parameter of a multiband Coplanar Waveguide (CPW)-fed antenna. The proposed square-shaped antenna-1 (Ant.1) and antenna-2 (Ant. 2) are primarily composed of three ground terminal stubs: Terminal-1 (T1), Terminal-2 (T2), and Terminal-3 (T3), all of which have an inverted L-shaped radiating patch. The proposed antennas' resonance frequencies (fr) can be adjusted by the electrical dimension and length of the stub resonators, the dielectric constant (εr) of substrate materials, and their appropriate thicknesses. It will have an impact on their return loss (|S11|), Impedance Bandwidth (IBW), radiation pattern, and antenna performance in terms of frequency characteristics, as demonstrated in this article. The proposed structure based on Flame-Retardant fiber glass epoxy (FR4) substrate covered a wideband frequency range from 1.5 to 3.2 GHz, (IBW = 1.7 GHz) and from 3.4 to 3.65 GHz (IBW = 0.25 GHz). The total IBW is 1.95 GHz, at S11 ≤ −10 dB with three resonance frequencies of values fr1 = 1.75, fr2 = 2.65, and fr3 = 3.50 GHz) for triple-band applications. The results are compared with the research work reported earlier. The proposed Ant.1 ensured, dual and triple band applications whereas the proposed Ant. 2 ensured dual, triple and quad bands applications with reasonable antennas' sizes similar to the earlier reported works. Furthermore, the impacts of various substrate materials as well as different lengths of multi-stub resonators on the operating bands and resonance frequency are thoroughly explored and analyzed for these antennas.

This paper presents the development of a metamaterial‐based microwave sensor for dielectric constant measurements. The sensor is constructed with a circular split‐ring resonator on one side and a coplanar waveguide transmission line on the other side. The proposed sensor has a size of 35 mm × 35 mm × 1.27 mm and resonates at 3.31 GHz. The sensor is fabricated on a RO3210 substrate with a dielectric constant of 10.2 and a loss tangent of 0.003. Both the simulation and experimental measurements show a linear relationship between the shift of the resonance frequency and the dielectric constants of the test samples, with a coefficient of determination R2 above 0.99. The dielectric constant of an unknown material can therefore be easily estimated using the inverse linear regression model. To validate the performance of the sensor, three known substrate materials, namely, Rogers RT6002, FR4, and Rogers TMM10, were used as test samples. The measured dielectric constants for these three materials were 2.8045, 4.3775, and 8.8719, respectively. The results agree closely with those indicated in the data sheets, with discrepancies of less than 5%. [ABSTRACT FROM AUTHOR]

This paper presents a tapered dielectric rod antenna excited by a folded dipole coplanar waveguide operating at terahertz frequencies. The effective refractive index of the plasmonic transmission line is obtained by two numerical methods, the Finite Element Method and the Finite-Difference Time-Domain, and it is used to obtain the dimensions of the gap connected to the line. We examine the antenna using two lengths of the rod. For 10 and 5 μm tapered rods, impedance bandwidths of 43.47% and 32.55%, maximum gains of 12.58 and 9.84 dB, and radiation efficiencies of more than 72.09%, and 72.15% are achieved, respectively. The dielectric rod nanoantenna operates at all the optical communication band frequencies: original (O), extended (E), short (S), conventional (C), long (L), and ultra-long (U). The structure of the antenna consists of three layers. The substrate is made of silicon oxide. This paper discusses the effect of using a layer of silicon oxide to prevent direct contact between the silicon rod and the hollow T-shaped silver feedline. [ABSTRACT FROM AUTHOR]

In this study, split ring resonator (SRR) based coplanar waveguide (CPW) fed antenna for 5.8 GHz radio frequency identification applications is presented. The antenna has a compact size of 18 × 12 × 0.8 mm3 on an FR‐4 substrate. The proposed antenna has been simulated in HFSS 2019 R2 EM simulator. Scattering parameter retrieval method has been used for the analysis of metamaterial unit cells. Return loss, E‐plane and H‐plane radiation patterns of the proposed antenna have been analyzed. The proposed antenna provides good radiation efficiency of 97.5% at an ISM frequency of 5.8 GHz. [ABSTRACT FROM AUTHOR]

In this article, an ultra-compact monolithic microwave integrated Wilkinson power divider (WPD) was accomplished for X-band applications. So as to reduce the size of the design, the miniaturization technique was illustrated with the theoretical analysis. After the theoretical analysis, the layout of the design and electromagnetic simulation were performed. The proposed Wilkinson power divider was manufactured with utilizing gallium nitride integrated passive device technology. In the measurement results, it was seen that the input and output (I/O) reflection coefficients were better than -15 dB in the frequency bandwidth of 8-12 GHz. In addition, the transmission coefficient was measured less than -4 dB in the X-band (8-12 GHz). Moreover, the 15-dB fractional bandwidth is 40% and the isolation between the outputs are better than -15 dB. The size of the proposed Wilkinson power was reduced to the dimensions of 700 m 700 m (0.0023 g x 0.0023 g, where g is the wavelength value at the center frequency (10 GHz)), as -type miniaturization technique was employed with monolithic lumped components. Beside its miniaturized size, the proposed power divider exhibits broadband characteristics while having any degradation in the electrical performance. [ABSTRACT FROM AUTHOR]

This paper presents a simple structure and small size antenna design with dimensions of 43x47 mm2 to perform an ultra-wideband (UWB) frequency range using a semicircular co-planar waveguide (CPW). This antenna has been designed and simulated by the computer simulation technology (CST) microwave studio suit. In this work, we design an ultra-wideband antenna (about 2 GHz to 10 GHz) by feeding a semi-circular compact antenna via a co-planar waveguide for input impedance of 50 Ω. The CST simulation results show that our designed antenna has a very good impedance and radiation characteristic within the intended ultra-wideband. Because of the small size and the suitable shape, this antenna can be used in many wireless communication applications, such as a radio frequency identifier (RFID), indoor wireless local area network or wireless fidelity (WiFi), internet of things (IoT), millimeter waves communications (mmWave), global positioning system (GPS), and many applications of 6G systems. [ABSTRACT FROM AUTHOR]

This paper proposes two flexible ultra‐wideband (UWB) multiple‐input multiple‐output (MIMO) slot antennas with connected ground and high isolation. Two MIMO antennas consist of two parallel slot antenna elements with coplanar waveguide feeds and ground. The antennas are etched on the liquid crystal polymer substrate and have the consistent sizes of 30 × 56 × 0.1 mm3. The first UWB‐MIMO antenna can cover 3–13 GHz. By adding a U‐shaped slot on the first antenna, a second UWB‐MIMO antenna with a notch‐band is designed, which can work in 3.2–13 GHz and filter the wireless fidelity frequency band (5–6 GHz). High isolation better than 20 dB is obtained by adding fence‐shaped branches. In addition, the performance of the flexible MIMO antenna is analyzed, including diversity performance parameters such as envelope correlation coefficient, diversity gain, gain, and total active reflection coefficient. The proposed UWB‐MIMO antenna can be applied in internet of things and wireless body area network frequency bands. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) enables the development of rapid, low-cost prototypes for ad-hoc and on-demand manufacturing to repair and keep up the continuous operation of systems, especially in time-sensitive scenarios where the system recovery cannot wait for the shipment of new components. Therefore, the industry, military, and academia continue to invest in these technologies to potentially achieve novel 3D geometries based on high-temperature dielectric and conductors to endure harsh environments, such as commonly found in the oil and gas, defense, and aerospace sectors. This paper reports the electromagnetic properties of 3D-printed Yttria-Stabilized Zirconia (YSZ) for 2–6 GHz and the DC and RF effective conductivity of sintered platinum ink, where the dissipative losses of the additively manufactured coplanar waveguides (CPWs) are less than 0.05 dB/mm when the frequency is below 4 GHz. In addition, the AM CPWs are exposed to thermal cycling up to 600 °C to study the material’s thermal fatigue and potential degradation. However, the samples do not exhibit appreciable degradation after thermal cycling. Also, a two-layer back-fed antenna based on 3D-printed YSZ and platinum ink is designed, manufactured, and tested. Results show a measured gain of 2.5 dBi and a front-back ratio of 9.6 dB at 4.1 GHz.

Aim: In this paper, isolation performance of rectangular shaped RF MEMS shunt and series switch is described and simulated at up to 30 GHz using HFSS software. Materials and Methods: The isolation performance of rectangular shaped shunt switch (n=25) was compared to the isolation performance of rectangular shaped series switch at a frequency range of upto 30 GHz. Beam was built over the two coplanar waveguides. Samples were calculated using sample computation having a pretest power of 80 % where Alpha, Beta are 0.05 and 0.2 respectively. Results: The novel shunt switch has better isolation performance (- 36.2488 dB) compared to the series switch (-19.4685 dB). The optimized dimensions for maximum isolation performance were L=360 µm, W=100 µm, T=1 µm for beam. The attained significance of isolation performance is 1<0.001 (p<0.05). Conclusion: The observed results show that novel shunt switch isolation performance is significantly higher than series switch. [ABSTRACT FROM AUTHOR]

In this letter a novel notched multi‐input‐multi‐output (MIMO) flexible slot antenna with a C‐slot is proposed and designed for wireless body area network (WBAN) and Internet of Things (IoT) applications. The proposed antenna is comprised of four similar elements with the feed line of coplanar waveguide (CPW). Antenna is printed on flexible liquid crystal polymer (LCP) substrate with compact dimensions. The proposed UWB‐MIMO slot antenna can operate in range of 2.85–10.85 GHz with notched band from 4.9–6.425 GHz. The achieved notched band can filter the interference of WLAN (5.15–5.825 GHz), by adding an inverted orthogonal branch, great isolation is achieved, which is better than 24 dB over working bands. What's more, the parameters of diversity performance like gain, envelope correlation coefficient (ECC) and diversity gain (DG) are also analyzed. The actual measurement of bending test and the effect of human body indicates that the presented antenna is suitable for WBAN and IoT applications. [ABSTRACT FROM AUTHOR]

This article presents a novel CPW fed ultrawideband (UWB) antenna for detection of unwanted tumor cells in the human breast. Here, a compact and miniaturized UWB antenna employed with dodecagonal edges is proposed for broadening the bandwidth from 2.26 to 13.71 GHz (measured fractional bandwidth of about 143.39%). The antenna is designed on a durable RT 5880 substrate having 0.254 mm thickness, efficiency of 85% and gain of 3.84 dBi. For its flexibility characterization, the prototype of the fabricated antenna is analyzed in both the flat and bending configurations. The simulated testing is carried out by permitting the antenna to emit radiation in conjunction to the human breast phantom to obtain desired antenna characteristics for the microwave imaging (MI) applications. The changes in reflection coefficient with the variation of dielectric content of the breast phantom structure are analyzed. The suggested antenna for MI technique is apt for human exposure because the antenna bids the highest SAR value of 0.932 W/Kg at 10.6 GHz. Moreover, the proposed antenna is flexible, compact and low‐profile with low SAR values that can be useful for breast cancer detection. [ABSTRACT FROM AUTHOR]

This communication presents a coplanar waveguide fed rectenna system implemented for efficient Radio frequency energy harvesting at 2.4 GHz Bluetooth/WLAN applications engrossing an overall dimension of 40 × 35 mm2. The antenna is designed on a rectangular patch having four slots etched on the radiator. Also, the ground is introduced with edge slots that are close to the feed line to improve the overall impedance bandwidth providing a gain of 4.12dBi. The E-plane corresponding to the radiation showcases dipole characteristics while the H-plane follows an omnidirectional pattern. The rectifying part comprises a hybrid Tripler circuit which is well matched with the L-shaped input impedance such that most of the received power could be deliberated. The results have demonstrated that the designed rectenna exhibits high conversion efficiency of 66.7% and output DC voltage of 3.47 V for load values of 3 kΩ at 2.4 GHz under the input power of 5 dBm. [ABSTRACT FROM AUTHOR]