Substrate Integrated Waveguide Cavity Research Articles

Single‐ and triple‐band bandpass filters using novel perturbed isosceles right‐angled triangular SIW cavities

Single‐ and triple‐band bandpass filters using novel perturbed isosceles right‐angled triangular SIW cavities

Compact bandpass filter based on single isosceles right triangular substrate integrated waveguide cavity and modified complementary compact microstrip resonant cell

Compact bandpass filter based on single isosceles right triangular substrate integrated waveguide cavity and modified complementary compact microstrip resonant cell

Design of Physically Connected Wideband SIW Cavity-Backed Patch Antenna for Wide-Angle Scanning Phased Arrays

A novel wideband substrate integrated waveguide (SIW) cavity-backed antenna element and its array are proposed in this letter. The proposed linearly polarized array element consists of a SIW cavity, stacked patches, and a coaxial probe. The SIW cavity-backed array element is implemented with physically connected stacked patch. The coaxial pin is directly connected to the two patch radiators. Blind and buried vias were avoided, this work significantly reduces the manufacture cost and complexity. The array features light weight and simple feed structure. The proposed element exhibits an impedance-matching bandwidth of 18.2% (14.5–17.4 GHz) for | S 11| H -plane with 8% bandwidth (14.4–15.6 GHz), under the criterion of active voltage standing- wave ratio (VSWR) ≤ 3. For verification purposes, a 4 × 16 active phased array antenna prototype is fabricated using the conventional microwave multilayer printed circuit board (PCB) process. The measured results agree very well with simulations.

Compact Dual-Band Dual-Mode SIW Balanced BPF With Intrinsic Common-Mode Suppression

In this letter, a compact dual-band dual-mode substrate integrated waveguide (SIW) balanced band-pass filter (BPF) with intrinsic common-mode (CM) suppression is designed by using a single perturbed SIW circular cavity. The vias and slot perturbations are introduced to tune the resonant modes TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">010</sub> , TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">110</sub> (a pair of degenerate modes), and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">210</sub> of a circular cavity. Thus, they can be used to form two differential-mode (DM) passbands with independently adjustable center frequencies and bandwidths. The SIW can be seen as a natural balun with intrinsic CM suppression. Furthermore, the planar differential excitation structure is designed to excite the perturbed SIW cavity. The CM noise cannot excite SIW cavity due to the characteristics of hybrid electromagnetic boundary. Finally, a compact dual-band dual-mode SIW balanced BPF at 8 and 10 GHz is designed and fabricated, and the measured results show good agreement with the simulated ones.

Miniaturized Cylindrical Open-Ended SIW Cavity Antenna and Its Dual-Band Applications

A cylindrical open-ended substrate-integrated waveguide (SIW) cavity is studied and analyzed in this work. Two orthogonally oriented gaps are used to shrink the dimension of the cylindrical open-ended SIW cavity. Then, the miniaturized cylindrical open-ended SIW cavity is used to construct dual-band antennas. One dual-band antenna is realized by a composite structure that supports two independent modes: they are the half-circular loop mode for the lower band and the half quasi TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11(1/2)</sub> mode for the upper band. The other dual-band antenna is an aperture-shared structure: the lower band is related to the miniaturized cylindrical open-ended SIW cavity which works at the quasi TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11(1/2)</sub> mode; the upper band is characterized by suspending a concentric slot-loaded circular patch which works at the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> patch mode over the empty space of the miniaturized cylindrical open-ended SIW cavity. All modes involved in the two dual-band antennas, the half-circular loop mode, the half quasi TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11(1/2)</sub> mode, the quasi TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11(1/2)</sub> mode, and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode, are featured by broadside radiation. The structures of the two dual-band antennas are easy to fabricate by using conventional printed circuit board (PCB) techniques and can be integrated with other planar circuits. Compared to other open-ended cavity antennas, the proposed cylindrical counterpart shows a more compact size and lower profile.

A Low-Profile Dual-Band Filtering Hybrid Antenna With Broadside Radiation Based on Patch and SIW Resonators

This paper presents a differentially fed dual-band hybrid antenna with broadside radiation, enhanced bandwidth, and high selectivity. The proposed antenna is constructed using a single-layer substrate based on rectangular patch resonator and substrate integrated waveguide (SIW) cavity. Herein, TM10 and TM12 modes of the rectangular patch resonator, together with TE21 and TE23 modes of the rectangular SIW cavity, are selected for resonances in the concerned dual-band radiation. Among them, TM10 and TE21 are employed for the lower passband, while TM12 and TE23 for the higher passband. Besides, for achieving broadside radiation performances in both bands, two arrays of shorting pins are loaded in the rectangular patch resonator and the constituted electric wall surround the rectangular SIW cavity is properly truncated to reshape the radiation patterns of TM12 and TE23, respectively. Notably, the resonant and radiation properties of all the involved modes are obtained with theoretical deduction. Furthermore, the cascaded trisection composed of the SIW cavity, the patch resonator, and the radiation impedance creates two radiation nulls in each upper stopband of both passbands and the mixed coupling between two resonators generates another radiation null to be located in the lower stopband of the higher passband. For demonstration, a prototype antenna with the dual bands at 3.5 and 5.8 GHz is fabricated and tested. The measured results show that the antenna has achieved an improved bandwidth (|Sdd11| < -10 dB) from 3.26 to 3.58 GHz and 5.60 to 5.90 GHz, respectively, with stable broadside gains of around 8.5 dBi. In addition, in the stopband, three radiation nulls are created at 3.71, 5.32, and 6.12 GHz for effective enhancement of dual-band frequency selectivity.

Designing of Novel Eighth-Mode Forth-Order Substrate Integrated Waveguide Band-Pass Filter with High Selectivity

A fourth-order Substrate Integrated Waveguide (SIW) filter has been presented in this research work. The four Eighth-Mode (EM) SIW cavity resonators have been electrically coupled and source to load coupling has been achieved by a slight modification of the eighth-mode resonator cavity. Here a 87.5% size reduction has been achieved using the EMSIW, which plays a significant role in achieving miniaturized structure. The operating center frequency is 13.5 GHz with a 3dB bandwidth of 0.5 GHz. The Rogers-5880 substrate has been utilized with relative permittivity of 2.2. The results show that the filter has three transmission zeros on either side of the pass-band, which gives high selectivity and a high out of band rejection.

Tri-fed SIW based self-triplexer antenna for X-band applications

In this letter, an efficient and electrically compact cavity-backed self-triplexing antenna using a substrate integrated waveguide (SIW) technique is proposed. The antenna model is nested with an inverted “T”-shaped cavity and convert the rectangular SIW cavity into the two quarter mode (QM) and a half mode cavity (HM) approximately; excited through a coax probe and two micro-strip feed line separately. The proposed model operates at three distinct frequencies at 9.37 GHz, 9.86 GHz, and 10.36 GHz used for X-band wireless and radar communication systems. The self-triplexing feature is obtained with the mode perturbation concept and adequate intrinsic isolation of &gt;31 dB is observed among three input ports. The proposed antenna possesses a minimum frequency ratio, uni-directional radiation patterns with high gain, and better efficiency.

Wideband via-Loaded Cylindrical Open-Ended SIW Cavity Antenna

A composite cavity-based antenna is proposed and presented in this work. Three kinds of modes of the composite structure are involved to obtain a wide bandwidth: the ${\mathrm {TE}}_{11 {\scriptstyle {}^{\scriptstyle 1}}\hspace {-0.224em}/\hspace {-0.112em}{\scriptstyle 2} }$ cavity mode of a cylindrical open-ended substrate integrated waveguide cavity, the odd TEM mode generated by loading two rectangular via holes inside the cavity, and the higher-order loop modes (L3 and L5) of a circular ring detached from the cavity by a circumferential slot located at the cavity’s side wall. In the implementation of the antenna, slot coupling feeding methodology is applied, which also introduces a resonance for the bandwidth enhancement. A simulated fractional impedance bandwidth of 57.3% with $|{\mathrm{ S}}_{11}| dB from 24.9 GHz to 44.9 GHz is achieved ( $|{\mathrm{ S}}_{11}|= -9.7$ dB at $f=27.7$ GHz is ignored). The antenna has a broadside radiation pattern within the operating frequency band and a maximum simulated broadside gain of 10.6 dBi at ${f}=27$ GHz. Multi-layer technique and metallized via holes processing, which become commercial nowadays, are two critical techniques of the presented antenna. The simple structure is benefit of the fabrication and the integration with other planar front-end circuits. The antenna is fabricated and experimentally verified. A small difference is observed between the measurement and the simulation. A measured fractional bandwidth of 52% from 27 GHz to 46 GHz ( $|{\mathrm{ S}}_{11}|= -9$ dB at ${f}=29$ GHz is ignored) and a measured maximum broadside gain of 9.5 dBi are achieved.

Compact SIW-Based Self-Quadruplexing Antenna for Wearable Transceivers

This letter proposes a low-profile substrate integrated waveguide (SIW) cavity backed self-quadruplexing antenna for wearable transceivers. The full-mode circular SIW cavity is split into four unequal quarter-mode SIW (QMSIW) cavities using the two slots on the upper layer of the cavity. The proposed antenna uses C-shaped and arc-shaped slots of different dimensions in each QMSIW resonator to operate at wireless local area network bands (3.5, 4.9, 5.4, and 5.8 GHz). The measured gains are 4.4, 5.07, 5.40, and 5.7 dBi at 3.5, 4.9, 5.4, and 5.8 GHz, respectively. The antenna is simulated and optimized inside a 48 $\times \text{76}\times$ 21 mm3 rectangular device by keeping the device on the chest of a realistic human model. The proposed antenna has unidirectional radiation patterns in all four operating bands with low backward radiations. Thus, it has low specific absorption rate at all four operating bands.

Low Cross-Polarization SIW Slots Array Antenna With a Compact Feeding Network

A low cross-polarization-slotted substrate-integrated waveguide (SIW) cavity planar array antenna, which consists of four symmetrically arranged linear arrays, is presented in this letter. The linear array is fed through a coaxial probe located at the center of the SIW cavity, which ensures that two quasi-TE150 modes with approximate frequencies can be excited simultaneously. Therefore, the impedance bandwidth can be significantly improved by merging the two resonant frequencies. When the adjacent linear arrays are fed by reversed phase signals with uniform amplitude, extremely low cross polarization can be achieved in both E- and H- planes. The alternative reversed phase signals with uniform amplitude are simply generated by a compact SIW TE410 mode cavity. Measured results show that the proposed 4 × 4 planar array antenna achieves an impedance bandwidth ranging from 9.9 to 10.34 GHz. Within the operating band, the gain varies from 12.5 to 14.9 dBi. In E and H planes, the cross-polarization level is lower than -52.1 dB within the half-power beamwidth, and the sidelobe levels are below -13.4 and -18.4 dB, respectively. The aperture efficiency is up to 51.5%.

Compact Diplexers With Folded Circular SIW Cavity Filters

This work presents diplexers realized with folded circular substrate integrated waveguide (FCSIW) cavity filters. The properties of such cavities are analyzed, and empirical equations for calculating the resonant frequencies are given. The analysis relies on an even-/odd-mode decomposition. A 10-GHz filter is designed based on this approach. In the second step, its size is reduced, still maintaining the passband behavior. An asymmetric taper is used to connect two such filters to realize a diplexer. Two diplexers with center frequencies of 10/15 and 12/13.5 GHz are presented. The diplexers are several times more compact than comparable devices reported in the literature. The components are manufactured, and the functionality is demonstrated by simulation and measurements.

A Compact SIW Monopulse Antenna Array Based on Microstrip Feed

In this letter, a compact substrate integrated waveguide (SIW) monopulse antenna array based on microstrip feed is proposed. The antenna cell is composed of two layers of dielectric substrates, the model of the dielectric substrate is Rogers 5880. The TE20 mode is excited in the bottom SIW cavity, and the mirrored TE20 mode is used to realize the function of a monopulse comparator, which makes the structure of the antenna simple and superior in performance. Furthermore, an array is formed on the basis of the cell. The performance of the array was verified in simulated software and the prototype was fabricated for testing. The measured results are consistent with simulated results. The antenna works in the X-band, and the measured and beam gain reaches 16.4 dBi, and the null depth is 33.8 dB. The antenna aperture efficiency reaches 43%, which has great advantages compared with similar antennas.

A Class of Box-Like Bandpass Filters With Wide Stopband Based on New Dual-Mode Rectangular SIW Cavities

This article proposes a new class of box-like substrate integrated waveguide (SIW) filters with wide stopband. First, a two-pole doublet bandpass filter with one finite-transmission zero (FTZ) is proposed using a new planar dual-mode rectangular SIW cavity, which is realized by TE201 and TE103 modes. TE102, TE202, and TE104 modes are suppressed intrinsically by arranging feeding lines at the horizontal centerline of the dual-mode SIW cavity. Then, a four-pole box-section filter with one FTZ is proposed using one dual-mode and two single-mode rectangular SIW cavities, and the two single-mode cavities have different width-length ratios to further improve the stopband performance. To further improve the cutoff skirt, a new design method for five-pole quasi-elliptic SIW filter is proposed, which is achieved by the four-pole filter loaded by one single-mode SIW cavity. Some design examples with the center frequency of 10 GHz are presented to verify the performance of the proposed dual-mode SIW filters and the design method.

Dual band bandpass filter based on semi‐circular mushroom loaded substrate integrated waveguide

AbstractThis paper presents a dual band bandpass filter by loading two semi‐circular mushroom resonators (ScMRs) inside the cavity of a circular substrate integrated waveguide (SIW). TM101 and TM201 modes of the mushroom resonator loaded circular SIW cavity are excited to generate the first and second passbands respectively. As the proposed bandpass filter is based on circular SIW cavity, the passbands of the filter undergo relatively low insertion loss (IL) compared to other referred works. The selectivity is improved by generating four transmission zeros (TZs); two TZs are generated in between the two passbands by cross coupling the excited modes of the resonators and other two TZs are generated in lower and upper stopband by the source to load coupling. The passbands of the proposed filter are centred at 2.24 GHz and 4.35 GHz with 13% and 6.2% fractional bandwidth (FBW) respectively. A prototype of the proposed dual bandpass filter occupying a compact area of 0.3λ0 × 0.3λ0 is fabricated in Rogers RT/Duroid 5880. The measured minimum insertion losses for the first and second passbands are 0.9 dB and 1.1 dB respectively with a good agreement observed between simulated and measured results.

Triple-Mode Substrate Integrated Coaxial Resonator Based Bandpass Filter Featuring Flexible Transmission Zeros and Adjustable Bandwidth

This communication presents substrate integrated coaxial resonator (SICR) based triple-mode bandpass filters designed for K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</sub> -band. A self-shielded SICR based third-order filter is realized using two planar coaxial resonators (SICR) embedded in a substrate integrated waveguide cavity (SIW). Merging the TEM based mode of two SICR's with TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> mode of SIW significantly enhances the bandwidth in a compact size. A novel topology realized using short circuited metallic via connecting to the top conducting plane through a metal strip demonstrates high degree of flexibility in positioning the transmission zeros to improve the selectivity as well as extend the out-of-band rejection of proposed filter. The three experimental prototypes devised for K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</sub> -band with fractional bandwidth more than 23% demonstrate multiple transmission zeros for good selectivity and out-of-band rejection with low insertion loss in a compact form factor.

A Compact Substrate Integrated Waveguide Cavity-Backed Self-Triplexing Antenna

A low-profile and efficient substrate integrated waveguide (SIW) based self-triplexing antenna for Worldwide Interoperability for Microwave Access (WiMAX), fifth-generation (5G) and wireless LAN (WLAN) applications is proposed in this brief. The antenna consists of two SIW cavities, out of which one is embedded in the other. The outer SIW cavity is excited with $50\Omega $ microstrip lines while the inner cavity inside the outer one is excited through a $50\Omega $ coaxial probe. The proposed triplexing-antenna works at three different frequencies [3.5 GHz (WiMAX band), 4.8 GHz (5G band) and 5.4 GHz (WLAN band)]. The outer SIW cavity provides two resonances at 4.8 and 5.4 GHz, while the inner cavity generates resonance at 3.5 GHz. High isolation (>26 dB) between the three ports is observed upon excitation of one cavity mode ( $TE_{101}$ ) and one patch mode ( $TM_{10}$ ). The antenna posses high gain and efficiency for all three bands along with >16.1 dB front-to-back ratio (FTBR). The proposed model is fabricated for validation of the simulated results. A reasonable matching between the simulated and measured results is observed.

A Single-Layer Circularly Polarized Antenna With Improved Gain Based on Quarter-Mode Substrate Integrated Waveguide Cavities Array

In this letter, a single-layer right-hand circularly polarized (RHCP) antenna with low-profile and improved gain based on quarter-mode substrate integrated waveguide (QMSIW) cavities array is proposed and experimentally validated. The proposed antenna consists of a central microstrip patch and four QMSIW cavities with the same dimensions, which are directly cascaded to the central patch. The E-field distribution of the proposed structure is similar to that of a circular SIW cavity working in the high-order TM120 mode. Due to the in-phase equivalent magnetic currents array formed by the fringing electric field of the radiation edges, a high RHCP gain with very low cross polarization in the broadside is achieved. Because of the high-order working mechanism, the antenna can be fed by a coaxial probe directly without any complex power distribution network. Measured RHCP gain of the antenna is up to 10.4 dBi at the center frequency point 5.78 GHz, which is in good agreement with the simulated results.

Circular Polarized Square Slot Antenna Based on Slow-Wave Substrate Integrated Waveguide

The design of a compact substrate integrated waveguide (SIW) cavity-backed circular-polarized antenna using a slow wave structure is proposed in PCB technology. Based on a multilayer substrate, this topology includes internal metallized blind via holes connected to the bottom conductive plane, inducing the physical separation of electric and magnetic fields in the SIW cavity. Hence, a slow wave effect is obtained, allowing a 47% reduction of the antenna cavity in comparison with its classic SIW antenna counterpart. Moreover, by asymmetrically inserting an inductive via into the patch region, a degenerated mode allows both a circular polarization and an enlargement of impedance bandwidth. Measurements and simulations are in good agreement in terms of radiation pattern and circular polarization with a return loss of 15 dB and a gain of 4.8 dBic.

Miniature Dual-Band Substrate Integrated Waveguide Slotted Antenna Array for Millimeter-Wave 5G Applications

A compact substrate integrated waveguide (SIW) antenna array that operates at 28 GHz and 38 GHz is proposed for fifth generation (5G) applications. The proposed array consists of four SIW cavities fabricated on one single layer of substrate. Each cavity implements a rhombic slot and a triangular-split-ring slot, resonating on TE101 and TE102 modes at 28 GHz and 38 GHz, respectively. In comparison with dual-band SIW antennas in the literature, the proposed configuration depicts a miniature footprint (28.7 × 30.8 mm2) without stacking substrates. To excite the four cavities with equal power, a broadband power divider that supports the propagation of TE10 mode is designed. Accordingly, the impedance bandwidths are 26.6–28.3 GHz and 36.8–38.9 GHz. The measured realized peak gain over the lower and higher bands is 9.3–10.9 dBi and 8.7–12.1 dBi, respectively. The measured half-power beam widths (HPBWs) at 28 GHz and 38 GHz are 20.7° and 15.0°, respectively. Considering these characteristics, including dual bands, high gain, narrow beam widths, miniaturization, and single layer, the proposed antenna array is a suitable candidate for millimeter-wave 5G communication systems with the flexibility in switching operating frequency bands against channel quality variations.