Printed Ridge Gap Waveguide Research Articles

Novel High Efficiency V‐Band Pure TEM D‐PRGW Antenna for 5G mmWave Applications

ABSTRACTThis paper starts with the proposal of an enhanced version of a planar rectangular slot antenna fed by the quasi‐TEM printed ridge gap waveguide (PRGW), attended with a numerical study of a miniaturization procedure showing the limitations of the conventional PRGW‐based antennas. Then innovative solution is introducing a new miniaturized pure TEM wide‐band slot antenna utilizing double PRGW (D‐PRGW) technology; the proposed approach is self‐packaged and shows high potential for enhancing antenna performance, particularly in terms of bandwidth, gain, and compactness. This technology is featured with low loss, high performance, and compact size; it consists of surrounding the ridge area with a double layer of electromagnetic band gap (EBG) lattice instead of one to eliminate the surface waves effectively and keep the signal completely confined inside the ridge area with strict minimum rows of EBG. Therefore, a broad impedance matching bandwidth (|S11| ≤ −10 dB) of 33.33% is obtained from 50 to 70 GHz, which covers the unlicensed NR parts (n262; amp; n263) of the V band. Furthermore, the antenna achieves a peak gain of approximately 16 at 65 GHz while the overall efficiency remains above 90% across the entire operating frequency band. The high performance along with the compact size of this novel design makes it a good candidate for 5G wireless communications applications centered around 60 GHz.

A Wideband and Compact Millimeter-Wave Antenna Array Fed by Printed Ridge Gap Waveguide for 5G Applications

This paper proposes a printed ridge gap waveguide (PRGW)-based 2 × 2 millimeter-wave antenna array with broad bandwidth and compact aperture. A dual-resonance element consisting of a quarter circular and a quarter annular patch is initially designed. Subsequently, to reduce the cross polarization (XP) radiation and enhance the gain of the proposed antenna, a four-element array with symmetric arrangement is developed, leading to a decline in the normalized XP levels from -4.5 to -18.9 dB and from -4.4 to -18.7 dB in the xoz and yoz planes, respectively. In addition, a pair of parasitic shorted half-circular patches is loaded to improve the antenna gain in the highfrequency range. Finally, a PRGW feeding network is designed and applied to provide differential feeding for the planar array. To validate the reflection and radiation performance, an array prototype is fabricated, and experimental verification is conducted. Measurement results show that a -10-dB impedance bandwidth of 14.3% (26.0–30.0 GHz) is realized for the prototype, and an average realized gain of 9.8 dBi with low XP radiation is achieved by the proposed array.

A Stable-Gain Millimeter-Wave Fabry-Perot Antenna Based on Circular Polarizer-Integrated PRS with Positive Reflective Phase Gradient

In this paper, we present a millimeter-wave Fabry-Perot antenna with dual resonances, circular polarization, and stable gain. To achieve circularly polarized radiation, we integrate a receiver-transmitter circular polarizer into the partially reflective surface (PRS) of the antenna. The PRS is specifically designed with a positive reflective phase gradient, which contributes to a stable gain in the dual-resonance frequency band. For the radiation source, we adopt a linearly-polarized substrate-integrated waveguide cavity-backed slot fed by a printed ridge gap waveguide. Experimental measurements conducted on a fabricated prototype of the proposed antenna demonstrate its impedance and axial ratio bandwidths of 28.6–30.0 GHz and 28.6–29.6 GHz, respectively. Furthermore, the antenna exhibits a peak gain of 12.1 dBi and a gain fluctuation lower than 0.6 dB within the operational frequency band.

Design and Performance Analysis of Compact Printed Ridge Gap Waveguide Phase Shifters for Millimeter-Wave Systems.

This paper introduces compact Printed Ridge Gap Waveguide (PRGW) phase shifters tailored for millimeter-wave applications, with a focus on achieving wide operating bandwidth, and improved matching and phase balance compared to single-layer technology. This study proposes a unique approach to achieve the required phase shift in PRGW technology, which has not been previously explored. This study also introduces a novel analytical approach to calculate the cutoff frequency and propagation constant of the PRGW structure, a method not previously addressed. Furthermore, the utilization of multi-layer PRGW technology enables the realization of multi-layer beamforming networks without crossing, thereby supporting wideband operation in a compact size. The proposed design procedure enables the realization of various phase shift values ranging from 0∘ to 135∘ over a broad frequency bandwidth centered at 30 GHz. A 45-degree phase shifter is fabricated and tested, demonstrating a 10 GHz bandwidth (approximately 33% fractional bandwidth) from 25 GHz to 35 GHz. Throughout the operating bandwidth, the phase balance remains within 45 ± 5∘, with a deep matching level of -20 dB. The proposed phase shifter exhibits desirable characteristics, such as compactness, low loss, and low dispersion, making it a suitable choice for millimeter-wave applications, including beyond 5G (B5G) and 6G wireless communications.

Contactless Air-Filled Substrate Integrated Cavity-Backed Slot Antenna Array With Improved Printed Ridge Gap Waveguide Feeding Network

Contactless Air-Filled Substrate Integrated Cavity-Backed Slot Antenna Array With Improved Printed Ridge Gap Waveguide Feeding Network

Circularly Polarized Ka-Band High-Gain Antenna Using Printed Ridge Gap Waveguide and 3-D-Printing Technology

A low cost high gain circularly polarized antenna is proposed, the proposed antenna achieves a gain of 20-dBi, and an axial ratio bandwidth of 6.5%. The proposed antenna is extremely low in cost as it uses Printed Ridge Gap Waveguide (PRGW) technology. The use of PRGW technology suppresses the parasitic and back-lobe radiation from the feed, which maintains neat radiation characteristics for the radiating antenna. The structure is made of a Magneto-Electric (ME) dipole which illuminates a set of adjacent dielectric slabs. The diffracted fields from the edges of the dielectric slabs add up constructively with the ME dipole radiated fields in the boresight, and boost the gain of the ME dipole. Accordingly, the antenna structure relaxes the need for designing a feeding network by utilizing the diffracted fields from dielectric slabs edges. A 3D printed dielectric polarizer is used to further boost the gain and transform the polarization of the antenna to circular polarization. The antenna possesses a focused pencil-beam pattern that is well-suited for several mm-wave applications.

A Novel Low‐Loss Planar PRGW Crossover Design for 5G Applications

AbstractIn this paper, a planar 0‐dB crossover using printed ridge gap waveguide (PRGW) technology is proposed and designed for millimeter‐wave applications. PRGW as a quasi‐TE mode is considered as the modern guiding technology at high frequencies and for the 5G and other upcoming communications. A prototype of the proposed PRGW crossover working around 30 GHz is fabricated and measured to validate the simulated results. Comparing simulated with measured results, a good agreement is observed. The measured results demonstrate that the designed crossover offers an insertion loss of better than 0.5 dB over the whole operating frequency bandwidth from 29 to 31 GHz where the return loss level is better than 15 dB and the isolation level is less than −13 dB. Compared with the other reported crossover structures, the designed PRGW crossover features a wider bandwidth with a smaller and planar configuration.

Millimeter-Wave Filtering Metasurface Antenna Array With Printed RGW Technology

A millimeter-wave (MMW) printed ridge gap waveguide (PRGW) fed filtering metasurface antenna (MSA) array is presented for 5G applications. The MSA element consists of a parasitic loop and a stacked patch. The elaborately designed parasitic loop around MSA not only provides satisfactory lower stopband performance but also brings an in-band resonance. Meanwhile, another upper edge radiation null is generated by introducing two square-ring slots on the MSA, improving the suppression level. Therefore, with no extra filtering circuits, desirable filtering characteristics are achieved. A 1×4 filtering MSA array is fabricated and tested to demonstrate the concept. Based on measurement results, the array prototype exhibits an overall bandwidth of 27.2% within |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> |<-10 dB. Besides, the average tested gain of about 11.1 dBi is realized, and the gain suppression outside the passband exceeds 27 dB on both sides.

High Gain Fan-Beam Pattern Antenna Based on the Utilization of Diffracted Fields From Dielectric Slabs Edges for IoT and Sensing Applications

A high gain, low-cost antenna structure is designed for a smart car parking system. The antenna uses Printed Ridge Gap Waveguide (PRGW) technology, which is fully shielded, and suppresses any parasitic radiation from the feed, and minimizes back-lobe radiation. The proposed antenna uses a single MSL feed point, which eliminates the need for any complex feeding network design, and allows the antenna to be integrated easily with PCB transceiver circuitry. A novel technique for the design procedure is proposed, the technique provides a generalization of using either electric or magnetic excitations with dielectric or magnetic rectangular slabs. A unique physical insight accompanied with a thorough analysis of the propagation mechanism is provided. The technique has a significant impact on reducing the complexity of the feeding network. The realized structure is compact, low profile, and low cost. The beam pattern of the antenna is a Fan-Beam (Elliptical) pattern which is well suited for various sensing and Internet of Things (IoT) applications.

Graphene-based terahertz reconfigurable printed ridge gap waveguide structure

Graphene-based microwave devices have enabled reconfigurability, thus paving the way to the realization of flexible wireless terahertz systems with featured performances. Despite great progress in the development of graphene-based terahertz devices in the literature, high insertion loss and wide tunable range are still significant challenges at such high frequencies. In this work, we introduce the use of graphene to implement a reconfigurable printed ridge gap waveguide (RPRGW) structure over the terahertz frequency range for the first time. This guiding structure is suitable for both millimeter and terahertz wave applications due to its supporting quasi-TEM mode, which exhibits low dispersion compared to other traditional guiding structures. The presented solution is featured with low loss as the signal propagates in a lossless air gap, which is separated from the lossy graphene elements responsible for the reconfigurable behavior. In addition, this guiding structure is deployed to implement a tunable RPPGW power divider as an application example for the proposed structure.

Broadband millimeter-wave metasurface antenna array with printed ridge gap waveguide for high front-to-back ratio

A novel broadband metasurface (MTS) antenna array with high front-to-back ratio (FBR) is proposed for 28 GHz millimeter-wave applications. With slot pairs loaded on patch cells, an aperture-coupled slotted-mushroom MTS antenna is designed to obtain broadband radiation characteristics with a compact size. To suppress the backward radiation of this antenna, the printed ridge gap waveguide (PRGW) technology with a perfect magnetic conductor (PMC) shielding made of mushroom unit-cells underneath the microstrip feeding line is applied. On this basis, a 4 × 4 MTS antenna array with the PRGW feed network is developed. Simulated results show that the FBR can be highly improved by over 16 dB within the entire bandwidth. To validate the design, a prototype of the proposed antenna is fabricated. Measured results show that an FBR greater than 28 dB can be obtained over a 24% impedance bandwidth (from 24.9 GHz to 31.7 GHz) with the reflection coefficient less than −10 dB. The measured antenna gain ranges from 17 dBi to 19.2 dBi and the corresponding measured aperture efficiencies are 35% and 45.6%. The measured results also suggest that the proposed MTS antenna possesses −35 dB cross-polarization level and stable radiation patterns. In addition, the proposed antenna remains a very low profile of 1.7 mm (0.17λ0 at 28 GHz). All the achieved features indicate that the proposed MTS antenna is an important candidate for B5G and 6G wireless communication.

Design of an E-sectoral horn based on PRGW technology for 5G applications

AbstractE-plane sectoral horn antenna based on printed ridge gap waveguide (PRGW) technology is designed for 5G applications. It is implemented on the top plate of the PRGW structure to avoid the losses and dispersion associated with conventional feeding mechanisms. The quasi-transverse electromagneticPRGW-based antenna is excited through a planar microstrip transition. First, the single horn antenna element is introduced with the microstrip feeding section. It shows an impedance bandwidth of fractional bandwidth 26% from 45.7 to 55.4 GHz with the realized gain of 12.7 dBi and radiation efficiency of 90%. In order to maximize the realized gain, a four-element linear horn array is introduced. The same impedance bandwidth is maintained with the array having a gain of 18.6 dBi from 45.7 to 55.4 GHz. The overall antenna array performance in the entire operating frequency range is stable with a radiation efficiency around 85%. Three matching sections are implemented to achieve better impedance matching. One is used to match the horn with the feeding aperture via the PRGW line. Another section is designed to match microstrip transition with PRGW ridge. Finally, two-stage quarter wavelength transformers are required to match the power divider with the array feeding network. A prototype of single-element horn antenna was fabricated to verify the concept of the design. Simulated and measured results show that the proposed antenna can operate in the frequency band of 45–55 GHz with good agreement of radiation performance. Moreover, the proposed designs are implemented and simulated using two microwave simulation tools (CST and HFSS) to verify the radiation performance, which exhibits good agreement. The design of an E-sectoral horn antenna and its array with high gain based on PRGW is demonstrated for the first time which is considered a novel issue. It can be integrated with other passive and active elements in communication systems. Thus, it can be a valuable component in 5G communication due to its high gain, compact size and ultra-wide band.

Dual circular polarization 2 × 2 slot array antenna based on printed ridge gap waveguide technology in Ka band

In this paper a novel multi-layer slot array antenna based on printed ridge gap waveguide (PRGW) technology with dual circular polarization (CP) at Ka band is proposed. This antenna consists of five layers, two dielectric substrates as a transition from PRGW to coax line and a branch line coupler (BLC) as an antenna feeding network, and three metal layers as a coupling slot, 2 × 2-element slot array antenna and ground layer. Feeding network has two individual ports consists of a BLC that based on PRGW implemented. The operating frequency band of the antenna for S11 < −10 dB with the gain more than 11.5 dBi is 27–29 GHz which covers the 27.5–28.35 GHz band proposed by Federal Communications Commission (FCC) and can be a suitable antenna for 5G applications at this frequency band. Total aperture size of the array antenna is less than 1.15 × 1.15 λ2 at 28 GHz and total efficiency of it is better than 80 %. Two individual ports of the proposed antenna provide two isolated left- and right-hand CP with axial ratio (AR) less than 2 dB for each port in aforementioned frequency range, and the measured results indicated that the antenna can provide isolation more than 15 dB between two input ports.

Differentially Fed Dual-Polarized 2-D Multibeam Dielectric Resonator Antenna Array Based on Printed Ridge Gap Waveguide

In this article, a differentially fed dual-polarized dielectric resonator antenna (DRA) subarray excited by a substrate integrated waveguide (SIW) cavity is proposed. A #-shaped slot etched on the top wall of the SIW cavity is used to achieve the differential excitation due to the intrinsic field distribution of TE120 mode in the SIW. Based on the proposed antenna subarray, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> 2 dual-polarized 2-D multibeam DRA antenna array with simple structure is designed, fabricated, and measured, which can achieve high cross-polarization discrimination (XPD) in the direction of maximum radiation. To reduce substrate loss, the printed ridge gap waveguide (PRGW) technology is used to feed the SIW cavity. Two orthogonal PRGW Butler matrices are placed at different layers so as to realize 2-D beamforming scanning with dual-polarization. The SIW cavity is placed in the air gap of PRWG, which can increase the stability of the antenna structure. By cleverly combining the SIW cavity and PRGW structure, the proposed multibeam antenna array has the advantages of high XPD and high radiation efficiency. Measured results show that an impedance bandwidth of 10% (28.5–31.5 GHz) and a peak gain of 11.8 dBi are obtained. Also, the measured XPDs are 28.3 dB at the center frequency and larger than 19.2 dB over the band of operation. Besides, the measured radiation efficiency of 67% is achieved for both the polarizations at 30 GHz.

Analysis and design of ultra-wideband PRGW hybrid coupler using PEC/PMC waveguide model

In this paper, a new method to facilitate the design of Printed Ridge Gap Waveguide (PRGW) structures is introduced. One of the main difficulties in designing such structures is related to their simulation process which is really time and energy-consuming. Therefore, a suitable boundary condition is considered to bring about the primary structure without involving the bed of nails or mushroom unit cells. Using this technique, a wideband PRGW 3 dB hybrid double-box coupler is designed to serve in mm-wave frequencies at a center frequency of 30 GHz, which can be deployed for the next generation of mobile communication. The designed coupler provides a wide matching and isolation bandwidth with low output amplitude imbalance, which is unique in comparison with current couplers. The prototype of the proposed coupler is fabricated and measured where the simulation and measurement results show a good agreement indicating the strength of the proposed method in PRGW structure design as well. The measured results show the couplers achieve better than 10-dB return loss and isolation over the frequency range from 25 to 40 GHz (46% BW) with the power-split unbalance and phase error within ± 1 dB and ± 5°, respectively. In addition, square mushrooms are chosen here to satisfy the high impedance surface. Not only do they bring about larger stop bandwidth, but also their configuration facilitates the arrangement of them around the coupler. The proposed design has superb characteristics such as low profile, low loss, and easy integration with microwave circuits and systems that can be suitable for designing mm-wave beamforming networks.

Magnetoelectric Dipole Antennas Loaded With Meta-Lens for 5G MIMO Pattern Diversity Applications

This communication presents a unique design of a dual-polarized wideband passive beam-switching antenna at millimeter-wave (mm-wave) bands for multiple-input–multiple-output (MIMO) pattern diversity applications, which exhibits low correlation between the ports and a broad tilt bandwidth (BW). A magnetoelectric (ME) dipole fed by a printed ridge gap waveguide (PRGW) as a quasi-TE source is considered as the elementary antenna in the Ka-band. To achieve beam deflection in each quadrant, a four-port MIMO prototype consisting of four ME-dipoles, positioned perpendicular to each other, is integrated with a meta-lens that consists of three layers of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$12\times12$ </tex-math></inline-formula> dual-polarized split-ring resonators (SRRs) offset from the center of each antenna. The beamforming structure is able to generate four fixed beams, one in each quadrant at an elevation angle of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 40^{\circ }$ </tex-math></inline-formula> with respect to the broadside direction by exciting each port sequentially, while the other ports are terminated. Moreover, the proposed orthogonal structure contributes to low correlation between the four ports, while achieving dual-polarization, which highlights the suitability of the antenna for 5G mm-wave applications. The measured results from a fabricated prototype demonstrate a −10 dB impedance BW of 40% over 24–36 GHz, tilting BW of 32.2%, and a peak gain of 13.4 dBi at 29 GHz, while an isolation better than 30 dB is achieved over the whole frequency band. Moreover, a measured radiation efficiency in excess of 85% is obtained, due to the use of the low-loss PRGW feedlines.

Design and Analysis of A High Frequency Bow-tie Printed Ridge Gap Waveguide Antenna

Millimeter and microwave wave components are in high demand, which will have a substantial influence on the development of 5G networks. In this work, Ridge Gap Waveguide is used to develop a planar high-gain antenna. The main objective of this study is to develop a wideband, high-gain antenna capable of supporting the expected need for high data transmission in the future. For this reason, a thorough examination of PRGW has been presented, along with a series of high-gain antenna designs that have been extensively tested. In the future, this antenna array might be used for 5G connectivity, and it meets all mm-wave band specifications. We have designed a novel tri slotted PRGW antenna which size is small (3.256x3.256x0.03 mm3), but the gain, bandwidth, directivity and rad efficiency is high with respect to other larger PRGW antenna. Although the volume of the proposed antenna is small, also it provides better Gain, Directivity and VSWR with respect to the larger conventional PRGW antenna. Directivity, gain and rad efficiency is increased when the tri slot is mounted on the substrate. It can be said that this antenna is suitable for ultra-wideband wireless communications, remote sensing, satellite newsgathering, disaster management, etc.

Design and Analysis of A High Frequency Bow-tie Printed Ridge Gap Waveguide Antenna

Millimeter and microwave wave components are in high demand, which will have a substantial influence on the development of 5G networks. In this work, Ridge Gap Waveguide is used to develop a planar high-gain antenna. The main objective of this study is to develop a wideband, high-gain antenna capable of supporting the expected need for high data transmission in the future. For this reason, a thorough examination of PRGW has been presented, along with a series of high-gain antenna designs that have been extensively tested. In the future, this antenna array might be used for 5G connectivity, and it meets all mm-wave band specifications. We have designed a novel tri slotted PRGW antenna which size is small (3.256x3.256x0.03 mm3), but the gain, bandwidth, directivity and rad efficiency is high with respect to other larger PRGW antenna. Although the volume of the proposed antenna is small, also it provides better Gain, Directivity and VSWR with respect to the larger conventional PRGW antenna. Directivity, gain and rad efficiency is increased when the tri slot is mounted on the substrate. It can be said that this antenna is suitable for ultra-wideband wireless communications, remote sensing, satellite newsgathering, disaster management, etc.

A Wideband Low-Profile Millimeter-Wave Magneto-Electric Dipole-Like Array With Low Transmission Loss Feed Network

A wideband millimeter-wave magneto-electric dipole-like array with low-profile is presented in this letter. The unit is fed by twin lines located on the same dielectric plate as the shorted patches, making the antenna have a low profile (0.13 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</sub> ). Furthermore, by using the butterfly patch and staggered arrangement, the impedance bandwidth of the designed unit can cover 23.9–46.75 GHz (64.7%), and the broadside gain is 5.5 ± 1.1 dBi. Then, a power divider based on the printed ridge gap waveguide (PRGW) is used to excite the 1×4 array. Finally, the designed array is manufactured and tested. The measured results are in good agreement with the simulated ones, showing that the working bandwidth of the array combined with the feed network can cover 24.5–40 GHz (48%), while the broadside gain is 7.73–12.65 dBi.

Ultra-Wideband Hybrid Magneto-Electric Dielectric-Resonator Dipole Antenna Fed by a Printed RGW for Millimeter-Wave Applications

Future communication standards have an increasing interest in Millimeter Wave (mm-wave) bands, where wide bandwidth and secured communication can be assured. This trend in communication standards stimulates the research community to provide novel antenna configurations in the mm-wave bands. This article proposes a novel design and analysis of hybrid magneto-electric dielectric-resonator dipole antenna that features an electrically small size with ultra-wideband operation and consistent radiation characteristics in the mm-wave band. The proposed antenna is designed based on the combination of multi-resonances produced by a Magneto-Electric (ME) dipole and stacked Dielectric Resonator Antennas (DRAs). In addition, the proposed antenna is implemented using state-of-the-art Printed Circuit Board (PCB) technology, namely, Printed Ridge Gap Waveguide (PRGW) for low loss and cost-efficiency. The combination between the ME-dipole and stacked DRA is adopted to ensure symmetric radiation characteristics in both E- and H-planes over ultra-wideband operation with a deep matching level. Both DRA and ME-dipole elements are designed and studied separately, where a systematic design procedure is presented to obtain initial design parameters. Proper integration between the radiating elements introduced an electrically small size antenna ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.64\,\,\lambda \times 0.48\lambda $ </tex-math></inline-formula> ) covers the full Ka-band (26-40 GHz) with a matching level beyond −20 dB and gain stability of 8± 1 dB. The antenna prototype is fabricated, where a good agreement is shown between both simulated and measured results.