Substrate Integrated Waveguide Resonator Research Articles

Planar dual-band bandpass filter with regular harmonic suppression

Abstract This paper presents a dual-band bandpass filter with regular harmonic suppression. The proposed third-order filter consists of two microstrip stepped impedance resonators and single substrate integrated waveguide resonator. The mismatches in their higher order resonant frequencies are utilized to suppress the regular harmonics. The passbands are centered at f1 = 2.4 GHz and f2 = 3.5 GHz with fractional bandwidths of 5% and 7.5%, respectively. The measured midband insertion and return losses are better than 2.55 and 14.5 dB for the first, whereas for the second band, they are better than 1.95 and 14 dB. The filter offers at least 33 dB suppression of first three higher order regular harmonics of f1 and f2.

Size-reduced substrate-integrated waveguide resonator designed using the quadrangular-star-slot metasurfaces

A particular kind of substrate-integrated waveguide (SIW) resonator is studied inspired by loading new quadrangular-star-slot metasurfaces (QSSMs). It is demonstrated that the QSSMs can effectively make the resonator electrically smaller. Good agreement has been observed between the numerical and experimental results for a specific QSSMs-loaded SIW resonator. It is revealed that the practical SIW resonator has a patch size of 0.585λg × 0.585λg, which is smaller than the conventional 0.707λg × 0.707λg. The QSSMs-loaded SIW resonators are simple to fabricate using the current print circuit board technology at a low cost.

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.

Solid Permittivity Measurement Sensor Based With IDE-ELC Substrate Integrated Waveguide Resonator

Solid Permittivity Measurement Sensor Based With IDE-ELC Substrate Integrated Waveguide Resonator

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.

Microwave substrate integrated waveguide resonator sensor for non-invasive monitoring of blood glucose concentration: Low cost and painless tool for diabetics

In this study, a microwave resonant sensor with an operation frequency of 9 GHz and a quality factor of 240 has been designed, fabricated and tested by fingertips of the users to control blood glucose levels. The proposed method includes the implementation of a band-pass filter in the substrate integrated waveguide cavity, which has been carried out using a modified split ring resonator. In this research, 4 volunteers with glucose level changes ranging from 92 to 141 mg dL−1 have been tested invasive (by a glucometer) and non-invasive (by the designed sensor). For this range of glucose level changes, the frequency detection resolution is 7.67 MHz (mg dL−1)−1.

Unloaded quality factor optimization of substrate integrated waveguide resonator using genetic algorithm

<p>The main objective purpose of this paper is to study the enhancement techniques of the unloaded quality factor of substrate integrated waveguide (SIW) resonator, given that the quality of filters depends first on the quality of the resonators that compose it. Performance enhancement is achieved by employing a MATLAB-based genetic algorithm to optimize the geometrical parameters of the SIW resonator by iterative convergence to the target frequency (10 GHz frequency). On the other hand, the Ansys HFSS tool is used to model and optimize the SIW resonator with the suitable transition and plot the S-parameters for a frequency sweep range to validate its property. The results obtained allow increasing the unloaded Q-factor to be more than 1609 and reducing not only insertion and return losses but also reducing the size of the resonator. The proposed SIW resonator with its small size and low loss is directly useful for microwave and millimeter-wave applications.</p>

Outside Front Cover: Plasma Process. Polym. 6/2023

Outside Front Cover: Microwave atmospheric pressure plasma jet generated from substrate integrated waveguide resonator by Chaoxia Zhao et al (e2200230).

Two-Layered Cross-Coupled Post-Loaded SIW Filter With Microstrip Ports

In this brief, we propose a new structure for reducing the number of substrates of a post-loaded substrate-integrated waveguide (SIW) resonator filters with microstrip ports. For using fewer substrates, the proposed structure has microstrip ports and each capacitive gap (the dielectric gap between one side of each post and the ground) on one side of the filter structure, which has not been reported to date. Hence, it does not necessitate another substrate designated for the implementation of the dielectric-filled gaps for the capacitive posts of post-loaded resonators. In addition, a new cross coupling structure for SIW resonators is also presented in this brief. Negative couplings can be easily implemented by using the proposed slot structure.

Microwave atmospheric pressure plasma jet generated from substrate integrated waveguide resonator

AbstractA microwave atmospheric pressure plasma jet (MW‐APPJ) generator based on a substrate‐integrated waveguide (SIW) resonator is proposed. A thin, straight plasma needle with a length of 9 cm could be obtained. Higher than 90% of microwave feeding efficiency is obtained under a wide range of gas flow rates without a microwave matching network. As the gas flow increased from 1 to 14 L/min, a transition from laminar to turbulent mode is observed in the plasma jet's morphology. Furthermore, a preliminary surface treatment was tested for the device. The polyimide film became super hydrophilic after a 5‐min treatment with the developed SIW‐based plasma generator. Generally, the SIW‐based MW‐APPJ is low‐cost, electrodeless, and low‐profile along the plasma jet length direction.

A Single-Layer Filtering Antenna With Two Controllable Radiation Nulls Based on the Multimodes of Patch and SIW Resonators

A single-layer filtering hybrid antenna with low profile and high selectivity is presented. The proposed antenna is composed of a triangular patch and a substrate integrated waveguide (SIW) cavity with triangular slot and U-shaped slot etched on the top surface. The patch is embedded in the triangular slot. Four modes can be generated by the hybrid structure. That is, the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode of the patch, the right half-TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> , the modified right half-TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> and the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.5, 1</sub> modes of the SIW cavity are selected. By merging the four modes into a single passband, the impedance bandwidth is broadened, and the frequency selectivity is enhanced. There are two radiation nulls at the lower and upper edges of the passband, which can be controlled independently. In addition, part of the shorting pins surrounding the SIW cavity is truncated to decrease the operating frequency and increase the out-of-band rejection. The measured –10 dB impedance bandwidth ranges from 3.44 to 3.62 GHz with sharp frequency selectivity and more than 18 dB out-of-band suppression level.

Low-Loss Self-Packaged Ka-Band LTCC Filter Using Artificial Multimode SIW Resonator

In this brief, a low-loss self-packaged Ka-band LTCC filter is proposed based on an artificial multi-mode substrate integrated waveguide (SIW) resonator. Two ridges and two metal strips are tightly integrated in one SIW cavity to form the artificial quad-mode resonator. Due to the shielding of the SIW cavity, the resonator realizes a high Q factor, which contributes to an extremely low loss of the Ka-band filter. A fast design method for the bandpass filter based on an artificial multi-mode resonator is introduced. A simple approach to accurately extract all external Q factors for multiple resonant modes at the same time is also discussed. A pair of transmission zeros are generated to improve the filter skirt selectivity. For verification, a filter operating at 28 GHz is fabricated on the LTCC process. The measured result shows a low insertion loss of 0.8 dB, which is attracted in millimeter-wave applications.

Design and Implementation of Graphene-Based Tunable Microwave Filter for THz Applications.

A reconfigurable Substrate-Integrated Waveguide (SIW) filter operating in the THz region was designed in this work. Two SIW resonators were coupled through a magnetic iris to form a second-order filter with a double-layer substrate. The first substrate was silicon of permittivity 11.9; on top of it, silicon dioxide of permittivity 3.9 was placed. The ground and upper plane were composed of gold plates. Graphene material was then used for the tunability of the filter. A thin graphene sheet was sandwiched between the silicon dioxide substrate and the upper gold plate. An external DC bias voltage was then applied to change the chemical potential of graphene, which, in turn, managed to change the operational center frequency of the filter within the range of 1.289 THz to 1.297 THz, which translated to a bandwidth range of 8 GHz. The second part of this work centered on changing the aspect ratio of the graphene patch to change the center frequency. It was observed that the frequency changed within the range of 1.2908 THz to 1.2929 THz, which gave a bandwidth of 2.1 GHz change.

Planar substrate integrated waveguide‐based resonators and its usage to compact X‐band small phase noise oscillator

AbstractThis study denotes a procedure of a small phase noise (SPN) oscillator employing three different substrate integrated waveguide (SIW) resonators as a frequency stabilization‐component. The SIW resonator as modifying phase noise (PN) is investigated and branchline coupler in the feedback loop is presented. The design technique to attain SPN usage for optimized efficiency is proposed. Then, three different X‐band SIW oscillators using a packaged GaAs FET transistor are planned. Due to the PN and compacting, the miniaturized conventional SIW (MCSIW) oscillator is selected. This MCSIW oscillator operates at 8.15 GHz, mentions a PN of −169 dBc/Hz at 1‐MHz frequency‐offset.

A stripline hybrid dual‐capacitively loaded SIW resonator and its filter implementation

AbstractA stripline hybrid dual‐capacitively loaded (DCL) substrate integrated waveguide (SIW) resonator is proposed and analyzed in this letter. First, the fundamental mode (TE101) and two higher order modes (TE102 and TE201) are shifted lower through the capacitive perturbation effect. Extra Striplines are then integrated with the proposed DCL triple‐mode resonator to generate transmission zeros both below and above the passband. Subsequently, the proposed stripline hybrid DCL SIW resonator is used to design an example fourth‐order filter with three transmission zeros. A step‐by‐step design guideline is then summarized under specified filter performance. Finally, to verify the proposed design method, an example fourth‐order bandpass filter at 5.5 GHz with an improved lower rejection band is designed, fabricated, and measured. The measured results indicate that this filter has the advantages of compact size, good selectivity, and easy three‐dimensional integration.

Varactor–Graphene-Based Bandpass Filter With Independently Tunable Characteristics of Frequency and Amplitude

This article presents a frequency–amplitude independently tunable bandpass filter (BPF). The filter uses an electrically tunable coaxial substrate integrated waveguide (SIW) resonator, which has a compact size and a constant fractional bandwidth (FBW). The surface-gap coaxial SIW resonator is loaded with eight varactors and a thin graphene sheet at the top and bottom, respectively, which results in possessing independent tuning characteristics of frequency and quality factors. The variable capacitance values of the varactor are used to achieve frequency reconfigurability, and the graphene located on the bottom surface of the resonator is equivalent to a tunable lumped resistor used to control the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -factor. In addition, detailed steps of BPF design are provided. For validation, a prototype third-order varactor–graphene-loaded multitunable coaxial SIW BPF is fabricated. The measurements show that within the tunable range of the varactors, the proposed filter can be tuned from 0.68 to 1.03 GHz with 5% ± 0.2% 1-dB FBW and the insertion loss of passband can be continuously tuned over 2.68–6.37 dB. The frequency tuning and amplitude tuning functions are not dependent on each other. Over the frequency tuning range, the transmission amplitude at an arbitrary center frequency can be dynamically tuned by controlling the bias voltage applied to the graphene.

SIW-Based Self-Quadruplexing Antenna for Microwave and mm-Wave Frequencies

A low-profile substrate integrated waveguide (SIW) cavity backed self-quadruplexing slot antenna supporting both microwave and millimeter (mm)-wave frequencies is proposed. Initially, a square SIW resonator is designed, and diagonally bisected into two half-mode resonators. A small portion of each section is assigned for mm-wave frequencies (28 and 30 GHz), and the remaining parts are adjusted to operate at microwave frequencies (4.8 GHz and 5.4 GHz). The microwave frequencies utilize the fundamental mode of the cavity and attain a maximum gain of 5.4 and 5.2 dBi at 4.8 and 5.4 GHz, respectively. The mm-wave resonators take advantage of higher order mode, resulting in a realized maximum gain of 8 and 8.7 dBi at 28 and 30 GHz. The simulated and measured results verified that at the mentioned frequencies, the reflection coefficients are below <inline-formula><tex-math notation="LaTeX">$-$</tex-math></inline-formula>20 dB, and the isolation among ports is better than 20 dB as well. Thus, it is asserted that the suggested antenna is a good candidate for fifth-generation (5G) communication systems utilizing sub-6 GHz and mm-wave bands. This can be considered as the first self-quadruplexing antenna designed for both microwave and mm-wave frequencies.

A compact tri‐band filter based on a dual‐capacitively loaded triple‐mode substrate integrated waveguide resonator

This letter presents a compact tri-band filter using a dual-capacitively loaded (DCL) substrate integrated waveguide (SIW) triple-mode resonator. The frequencies of TE101, TE102, and TE103 are shifted lower by the capacitive loading effect, which is achieved by the DCL structure. A compact tri-band example filter is then built by using two DCL triple mode SIW resonators. Following that, seven transmission zeros are generated to improve filter selectivity by vertical coupling of two cavities. The area of the filter occupies only 0.46 λg2. The measured results demonstrate that this compact tri-band filter has the advantages of flexible control of passbands, easy interconnection with other planar radio frequency components, making it promising for millimeter wave implementations and 3D-integrated systems.

Varactor-graphene-based multi-reconfigurable triplet filter with independent tuning of frequency and amplitude

In this paper, a multi-reconfigurable filter which consists of three identical varactor-graphene-loaded coaxial substrate integrated waveguide (SIW) resonators is presented. The center frequency and transmission amplitude of the proposed filter is independently reconfigurable by means of electrically controlling the values of the varactor capacitance and the graphene resistance, respectively. Tuners and their bias circuits are mounted on the surfaces of the SIW resonator to adjust the tuning of resonant frequency and unloaded quality factor, which enable to realize the frequency and amplitude of the presented multi-reconfigurable filter. In addition, the proposed filter applies a cascaded triplet topology to generate a transmission zero at the upper side in order to enhance skirt selectivity and out-of-band rejection. The circular shape of the resonator provides great flexibility and produces an additional compactness of the filter. The proposed multi-reconfigurable coaxial SIW filter is designed and fabricated, with high-Q varactors and graphene thin sheets as frequency and amplitude tuning elements, respectively, exhibiting the following reconfigurable characteristics: (a) a wide tuning range of 0.58–1.01 GHz with a constant 1 dB fractional bandwidth of 2 ± 0.2%. (b) A continuous tuning range of amplitude at any center frequency in the achievable frequency band. For instance, the proposed filter can be tuned with an amplitude range of 3.02–19.8 dB by varying the value of the graphene sheet resistance at 1.01 GHz. (c) Free combination of the arbitrary center frequency and attenuation level. The proposed filter with tunable filtering and attenuating responses has widely potential in reconfigurable wireless communication systems and radar systems due to its high integration and versatility.

Design and Analysis of Compact 5th Mode Balanced Substrate Integrated Waveguide Band-Pass Filter for 39 GHz

This paper presents a balanced fifth-order Substrate Integrated Waveguide (SIW) band-pass filter operating at 39 GHz. The filter uses the balanced nature of the SIW resonators and the odd-mode property of the TE102 mode. Five rectangular resonators have been used to develop a fifth-order band-pass filter and the couplings between them with the external quality factors have been determined. The filter yields a good response in the KA band of the electromagnetic spectrum. It has a smaller footprint and operates at a higher frequency range compared to other filters with the same technology. The Common-Mode (CM) signal has been effectively suppressed to more than -30 dBs throughout the considered range. The return loss of -30 dBs and an insertion loss of -4 dBs for the Differential-Mode (DM) operation are achieved at the operating frequency of 39 GHz. The half-mode operation of the filter has been also implemented and the results have proven to be satisfactory.