Substrate Integrated Waveguide Cavity Research Articles

Improving Scanning Performance of Patch Phased Array Antenna by Using a Modified SIW Cavity and Sequential Rotation Technique

Improving Scanning Performance of Patch Phased Array Antenna by Using a Modified SIW Cavity and Sequential Rotation Technique

Low sidelobe planar electrically large sparse array antenna with element number reduction based on genetic algorithm

AbstractConventionally, both electrically larger (EL) arrays and sparse arrays offer the advantage of element number reduction but disadvantage of high sidelobe levels. A new scheme of planar EL sparse array antenna based on a genetic algorithm (GA) to achieve low sidelobe with element number reduction is proposed. To begin with, EL sparse array antenna optimisation models based on GA for both linear and planar arrays are analysed. Then, an EL slot antenna element based on a 3 × 3 substrate integrated waveguide cavity is designed. An 8‐element linear EL sparse array antenna is designed and compared with a uniform array antenna, demonstrating a reduction in the maximum sidelobe level (MSLL) by nearly 4.6 dB. After that, a 4 × 8 element planar EL sparse array antenna is fabricated and measured. Compared to an 8 × 16 element planar EL uniform array antenna, the number of antenna elements is reduced by 75%, while the MSLL is reduced by approximately 3 dB. The measured −10 dB impedance bandwidth ranges from 25.3 to 27.8 GHz. At the central frequency, the radiation pattern achieves a peak gain of 29.6 dBi, exhibiting low sidelobe levels below −15.0 dB.

Substrate integrated waveguide-based self-triplexing antenna-sensor

In this paper, a Substrate Integrated Waveguide (SIW) based self-triplexing antenna-sensor is introduced. The proposed structure can act as a sensor for concurrent detection of three chemical materials. Further, it can be used as a self-triplexing antenna for simultaneous operation at three different frequencies. To that end, initially, a half mode circular SIW cavity is designed. Then, it is divided into three parts. In each part, the position of maximum electric field is determined and subsequently, three holes are located in the positions for material insertion. Finally, considering the vacuum as the inserted material for each hole, each cavity is adjusted to operate at its operation frequency (4.8, 5.8, and 6.6 GHz). Altering the permittivity of the objects inserted in the holes, the resonant frequencies are changed and consequently the type of material is determined. The simulated and measured results validated the performance of proposed antenna-sensor as well. In all the frequency bands, the reflection coefficients as well as mutual coupling among ports are below −20 dB. It should also be expressed that such an SIW structure with the capability of sensing and propagation is provided for the first time.

Multilayer circular SIW cavity differential bandpass filter with wide‐stopband characteristics

AbstractIn this paper, a compact differential bandpass filter with wide‐stopband is presented. The proposed differential filter is designed using two circular substrate‐integrated waveguide (SIW) cavities coupled through a pair of symmetric coupling slots. The filter operates in TM110 mode of the circular SIW cavity. The degenerate TM110 mode is shifted to higher frequency by the introduction of two pairs of perturbation vias. The center frequency of the differential passband can be tuned by changing different design parameters such as location of perturbation vias and length of the slotlines. As a proof of the proposed concept, a second‐order differential bandpass filter is designed, fabricated, and measured. The measured results are in good agreement with the electromagnetic‐simulated ones.

A dual‐wideband 5G antenna with dual polarization in the sub‐6 GHz band and 2 × 2 MIMO function in the 28‐GHz band

AbstractA novel aperture‐shared dual‐wideband 5G antenna with dual polarization in the sub‐6 GHz band and multi‐input multi‐output (MIMO) function in the 28‐GHz band is presented in this work. A dual‐polarized megnetoelectric dipole (ME‐dipole) with wide bandwidth is introduced in the sub‐6 GHz band. Based on the partial structure reuse method, four 2 × 2 substrate integrated waveguide (SIW) cavity‐backed patch arrays are integrated into the electric dipole structure of the ME‐dipole to construct a 28‐GHz 2 × 2 MIMO system. Two high‐order SIW cavity modes that cooperate with patch modes are used to enhance bandwidth in the 28‐GHz band. For demonstration, a prototype of the proposed antenna was fabricated and measured. The simulated results are in good agreement with the measured results, showing wide bandwidths of 39.6% and 10.85% in the sub‐6 GHz and the 28‐GHz bands, respectively. In addition, excellent measured in‐band and cross‐band isolations of over 44.4 dB and 45.2 dB are obtained, respectively.

Integration of two dual-port substrate integrated waveguide based MIMO antennas on a common substrate for 5G millimeter wave applications

Abstract This paper presents method for integrating two dual port multiple input multiple output (MIMO) antennas on a common substrate based on substrate integrated waveguide (SIW) technology. One of the dual port MIMO antennas (MIMO_1) resonates at 31.2 GHz with an impedance bandwidth of 1 GHz while the other dual port MIMO antenna (MIMO_2) exhibits an impedance bandwidth of 925 MHz and resonates at 36 GHz. The radiators etched on the SIW cavities are complementary slotted annular rings (CSAR). Isolation between the ports is more than 20 dB which is inherently achieved by SIW cavity backed structures. The MIMO antenna realized at 31.2 GHz exhibit a peak realized gain of 8.5 dBi while the MIMO antenna realized at 36 GHz displays a peak gain of 9.8 dBi. The diversity gain of both the MIMO antennas is around 9.9 dB and the envelope correlation coefficient (ECC) of the MIMO antenna realized at 31 GHz is below 0.004 while the ECC of MIMO antenna at 36 GHz is below 0.006. It is also confirmed that simulated results closely correlate with the measurement results.

Compact Integrated Circular Polarization Filtering Antenna based on SIW Cavity

In this paper, a compact integrated circular polarization filtering antenna is proposed based on substrate integrated waveguide (SIW) cavity. Firstly, a dual-mode (TE102 and TE201 modes) rectangular cavity is utilized as a common feeding cavity to achieve a dual-mode filtering response. And then, an additional rectangular patch with a slot is coupled from the feeding cavity for circular polarization radiation. To verify the proposed concept, a prototype circular polarization filtering antenna is simulated. The circular polarized filtering antenna resonates at 4.225 GHz with a low cross-polarization and a high gain of 7.23 dBi.

Four-way SIW Filtering Power Divider with In- and Out-of-phase Characteristics and Large Power Division Ratio

A novel four-way substrate integrated waveguide (SIW) filtering power divider (FPD) with in-phase and out-of-phase characteristics and a large power division ratio (PDR) is presented in this work. The frequency selection and power division functions are effectively realized by employing SIW resonators at the bottom layer and at microstrip sections at the top layer, respectively. Four microstrip lines coupled with SIW cavity through a slotline realize in-phase and two out-of-phase output characteristics and a large PDR of 7:1. To verify the design method, a four-way prototype with PDR of 7:7:1:1 is designed, fabricated, and measured. Results exhibit good filtering performance, large power division ratio, and in-phase and out-of-phase characteristics.

Substrate integrated waveguide-based frequency-tunable self-octaplexing antenna

This communication presents the first-ever substrate integrated waveguide (SIW)-based frequency-tunable self-octaplexing antenna (SOA) for wireless communication. The structure is arranged by implementing eight distinct patches with planar 50-ohm feedlines at the top of the SIW cavity, which realize eight distinct resonant frequencies. Independent tuning of each resonant frequency is achieved by incorporating appropriately allocated pockets in the antenna substrate, which can be filled with solid dielectrics of different permittivity. The obtained tuning range is broad, from 4.76 GHz to 9.82 GHz, with the capability of tuning each port individually. Furthermore, the port isolation (for all ports) that is better than 20.5 dB. The proposed antenna has a realized gain of 3.91, 3.2, 4.05, 4.14, 3.8, 3.37, 3.55 and 3.28 dBi when using Rogers RT-6010 for pocket filling. Furthermore, the antenna provides stable radiation characteristics with precise tuning. The proposed device is suitable for various applications, including multi-standard wireless communications, due to its small size, wide tuning range, consistent radiation patterns, and comparable isolation levels.

Multilayer Packaged Single- and Dual-Band Dual-Channel Bandpass Filters Based on Substrate Integrated Waveguide Cavities

Multilayer Packaged Single- and Dual-Band Dual-Channel Bandpass Filters Based on Substrate Integrated Waveguide Cavities

Compact Hybrid Bandpass Filters Using Substrate-Integrated Waveguide and Stripline Resonators

This article presents a novel class of compact hybrid bandpass filters (BPFs) using substrate-integrated waveguide (SIW) and stripline resonators. As the stripline resonators are inserted between two SIW cavities, they are able to increase the filtering order without occupying any additional area. This is beneficial for circuit miniaturization. To verify the concept, several third-order hybrid filters with various responses are designed by combining a half-wavelength stripline resonator (HWSLR) or a full-wavelength stripline resonator (FWSLR) and two SIW resonators. Their sizes are reduced by more than 33% compared with standard third-order SIW filters. In addition, a class of fourth-order box-like hybrid filters with two flexible transmission zeros (TZs) is also proposed by using the HWSLR and FWSLR simultaneously. Compared with previously reported box-like SIW filters, a size reduction of more than 65% is obtained. Three filter prototypes are fabricated and measured for validation.

A Single-Layer Differentially-Fed Filtenna with Controllable Radiation Nulls Using Hybrid SIW Cavity and Patches

A Single-Layer Differentially-Fed Filtenna with Controllable Radiation Nulls Using Hybrid SIW Cavity and Patches

Design of Wide-Stopband and Dual-Band Filtering Crossovers Based on Mixed Substrate Integrated Waveguide Cavities

Design of Wide-Stopband and Dual-Band Filtering Crossovers Based on Mixed Substrate Integrated Waveguide Cavities

Substrate‐integrated‐waveguide cavity‐backed circularly polarized antenna with enhanced bandwidth and gain

AbstractWe propose a method for increasing the bandwidth of a substrate‐integrated‐waveguide (SIW) cavity‐backed antenna with taper‐based microstrip SIW transition feeding. For radio transmission, a circular slot is etched on top of the SIW cavity. For optimal antenna design, the slot is etched slightly away from the cavity center to generate circularly polarized waves. Simulations show a wide axial ratio bandwidth of 7.860% between 11.02 GHz and 11.806 GHz. Experimental results confirm a similar wide axial ratio bandwidth of 4.9% between 10.8 GHz and 11.35 GHz. An SIW feed from an inductive window excites the radiating circular slot, resulting in a simulated wide impedance range of 1.548 GHz (10.338 GHz–11.886 GHz) and bandwidth of 13.93%. Experimental results show a wide impedance of 2.08 GHz (10.2 GHz–12.08 GHz) and bandwidth of 18.84%. The SIW cavity‐backed antenna creates a unidirectional pattern, leading to gains of 6.61 dBi and 7.594 dBi in simulations and experiments, respectively. The proposed antenna was fabricated on a Rogers RT/Duroid 5880 substrate, and the reflection coefficient, radiation patterns, and gains were tested and compared using a computer simulator. The developed broadband antenna seems suitable for X‐band applications.

A multi-beam circularly polarised Fabry-Perot resonator antenna array using SIW for X-Band applications

ABSTRACT This paper presents a novel multi-layer beamforming antenna array based on Fabry-Perot resonator that is excited by a high-performance compact 4 × 4 Butler matrix using substrate integrated waveguide (SIW) technology for X-band application. The adapted ring patch antenna is fed through the aperture on a rectangular SIW cavity and forms the radiating element in the antenna array. Enhanced characteristics of the antenna array are realised by inserting an electromagnetic bandgap (EBG) structure between the radiating elements and a superstrate constituted from two complementary frequency selective surfaces (FSS) that forms a Fabry-Perot resonator (FPR). Circular polarisation in the proposed FPR SIW antenna array (FPRSAA) is achieved by using a combination of sequential phase rotation and orthogonal feeding techniques. Measured results of antenna array (Ant. II) show |S11| ≤ −10 dB between 8–12.0 GHz, a circular polarisation (CP) gain variation between 15.64–18.54 dBic, 3 dB axial-ratio between 8.5–11 GHz, and scanning angle covering −47 to 47 degrees.

Compact Tri-Band SIW Bandpass Filters With High Selectivity and Controllable Center Frequencies Using Perturbation Structure

In this paper, two compact tri-band substrate integrated waveguide (SIW) bandpass filters (BPFs) with high selectivity and controllable center frequencies are presented based on the proposed tri-mode SIW resonant cavity perturbed by metallized vias. The resonant characteristics of the tri-mode SIW cavity are first analyzed, and the impacts of some key parameters on the resonant frequency are comparatively analyzed to further elucidate the flexible controlling of the vias perturbated SIW cavity structure. For demonstrating the superiority of the proposed tri-mode SIW cavity, a prototype of tri-band SIW BPF, centered at 11.18, 12.61 and 13.33GHz, is designed using one-layer substrate. In order to further reduce the occupied size, a tri-band SIW BPF with controllable center frequencies of 11.93, 13.21 and 14.12GHz, is constructed based on electric and magnetic coupling structure using two layers substrates. Both of the proposed triband BPFs exhibit six transmission zeros (TZs), resulting in good out-of-band rejections. The measured results agree well with the simulated ones.

Wideband and Highly Selective BandPass Filter Using Substrate Integrated Waveguide Technology for Ku-Band Applications

A new compact design of bandpass filter using substrate integrated waveguide (SIW) is proposed and analyzed in this paper. It offers good in-band return loss, low insertion loss, wide passband, and high stopband attenuation. The filtering response is achieved by loading a couple of inverted tuning fork-shaped defected ground structures (DGS) on the bottom of the SIW cavity. DGS is utilized to enhance the upper stopband performance. To validate, the filter is fabricated using Rogers RT/Duroid 5880 with 0.508 mm thickness and tested. The filter has a center frequency of 15.44 GHz with 19% fractional bandwidth (FBW). The return loss is more than 20 dB and the insertion loss is about 1.2 dB. It finds its application in Ku band satellite communication.

A new electric coupling and its applications on millimeter-wave SIW filter with high selectivity and controllable TZs

In this paper, a novel simple horizontal electric coupling (SHEC) structure is proposed, which only requires a single elliptical ring slot to be etched at the top layer of the substrate between the two adjacent SIW cavities. The working mechanism of SHEC is revealed using the equivalent magnetic current theory. The results indicate that the ring slot is divided into two semi-elliptical slots by the via-hole, and the induced electric fields generated by equivalent magnetic current near the slots enhance the extremely weak electric field intensity at the edge of the SIW cavities, resulting in the formation of electric coupling between the adjacent two cavities. As a verification, a fourth-order SIW filter operating at 27.96 GHz was designed based on the SHEC structure. The filter exhibits high selectivity with sharp roll-off of 114/105 dB/GHz and obtains controllable transmission zeros (TZs) by changing the size of the elliptical slot. Additionally, the proposed SHEC design has a regular via-holes arrangement and does not require etching slot on the bottom layer of the substrate, making it easy to accurately process, integrate, and package, providing a new approach for the design of millimeter-wave filters.

Wideband circularly polarized SIW cavity‐backed patches antenna for wide‐angle scanning phased arrays

AbstractA single‐feed wideband circularly polarized (CP) substrate‐integrated waveguide (SIW) cavity‐backed antenna and its phased array are presented in this paper. The proposed element consists of SIW cavity, stacked patches, and a 50‐Ω coaxial probe. The coaxial pin is directly connected to the two patch radiators. By chamfering on each rectangular patch, the proposed SIW cavity‐backed patch antenna realizes wideband circular polarization characteristic. The proposed element exhibits a simulated impedance bandwidth of 22.5% (14–17.6 GHz) for |S11| < −10 dB, an axial‐ratio (AR) bandwidth of 12.9% (14.5–16.5 GHz) for AR ≤ 3 dB. Simulation results illustrate that the infinite array can scanning up to ±60° in all planes over the operating frequency, under the criterion of active VSWR ≤ 3 and AR ≤ 3 dB. For verification purpose, an 8 × 8 array prototype was manufactured and measured. To achieve better CP characteristics, the sequential rotation technique is applied to the full array configuration. The measured results show good agreement with simulation results.

Design of Nonreciprocal Filtering Antenna Using Spatio-Temporal Modulated SIW Resonators

This article reports on, for the first time, the design of nonreciprocal filtering antennas using spatio-temporal modulated substrate integrated waveguide (SIW) resonators. It consists of two SIW cavities and a half-mode SIW (HMSIW) cavity, which is designed as the last-stage resonator and the radiator. By integrating time-modulated capacitors on the surface gaps of the three cavities, the nonreciprocal radiation patterns in transmission and reception modes are achieved at the same operating frequency. Three radiation nulls are generated due to the cross-coupling in the time-modulated network and source-load coupling. The theoretical analysis of the co-designed nonreciprocal SIW filtering antenna is detailed, along with methods for its co-simulations and measurements. For the proof-of-concept demonstration, a nonreciprocal SIW filtering antenna operating at 2.4 GHz is designed and fabricated. The measured 10-dB bandwidth and peak gain are 1.7% and 2.6 dBi, respectively. The measured realized gains at transmission and reception show that the reverse isolation is greater than 11 dB within a bandwidth of 30 MHz. The frequency selectivity values are 756 and 368 dB/GHz at the left and right sides of the passband, respectively.