Half-mode Substrate Integrated Waveguide Filter Research Articles

Compact Low-Loss Half-Mode Substrate Integrated Waveguide Filter With Controllable Transmission Zeros

Two novel planar filters with controllable mixed electromagnetic couplings are developed in this brief for C band operation. They are implemented with the half mode substrate integrated waveguide (HMSIW) technology. Owing to the half mode SIW cavity, both of the filters exhibit a compact size. The size of filter I is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.53\,\,{\boldsymbol{\lambda }}_{\mathbf {0}} \times 0.30 {\boldsymbol{\lambda }}_{\mathbf {0}}$ </tex-math></inline-formula> , while the size of filter II is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.47\,\,{\boldsymbol{\lambda }}_{\mathbf {0}} \times 0.28 {\boldsymbol{\lambda }}_{\mathbf {0}}$ </tex-math></inline-formula> . ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\boldsymbol{\lambda }}_{\mathbf {0}}$ </tex-math></inline-formula> represents the wavelength in the free space at the center frequency). A wide passband response with a quasi-elliptic characteristic and good out-of-band rejection is realized due to the transmission zeros (TZs) introduced by the etched slot structures on the top metal layer. By modifying the dimensions of the structure, the strength of the electric and magnetic coupling can be independently controlled, and consequently the position of TZs is controllable to achieve desired stopband response with high selectivity. As a validation of the concept, one prototype is fabricated and tested. Excellent agreement is observed between the simulated and measured results.

Triangular Cavity Multi-Passband HMSIW Filter Based on Odd-Even Mode Analysis

This letter proposes a multi-passband half-mode substrate integrated waveguide (HMSIW) filter based on the theory of odd and even mode analysis. The filter adopts a triangular HMSIW cavity cut along the diagonal of the rectangle. By etching two dual-mode resonators, the resonant mode of the HMSIW resonator is coupled with the odd-even mode of the dual-mode resonator to achieve multiple passbands. The defected ground structure (DGS) of the filter can reduce the resonance frequency of the HMSIW cavity without increasing the volume of the HMSIW cavity, making it easier to couple with the odd and even mode frequencies of the resonator. The input and output ports are directly coupled through a microstrip line. In this way, it adds an additional coupling path to the filter, which increases the out-of-band suppression without changing the performance in the passband, and improves the overall performance of the filter. To prove the feasibility of the above method, a multi-passband HMSIW filter was fabricated and tested. The center frequencies of the three passbands of the filter are 2.98 GHz, 4.78 GHz, and 6.62 GHz, respectively. The return loss in the passband is better than −15 dB, and the insertion loss is better than 2 dB. The measured results have a good agreement with the simulation results.

Ultra-Compact Dual-Band Half-Mode substrate integrated waveguide filter and filtering power divider based on metamaterial concept

In this paper, a novel dual-band (DB) half-mode substrate integrated waveguide (HMSIW) filter and three novel equal/unequal DB HMSIW filtering power dividers (FPDs) based on the metamaterial concept with ultra-compact dimensions are proposed. The working principle of the proposed configurations is based on the theory of evanescent-mode propagation. Based on the metamaterial concept, a novel compact metamaterial unit cell with double negative permittivities by combining two different types of metamaterial unit cells has been introduced. By loading the proposed metamaterial unit cell with dual negative effective permittivities at different frequencies on the HMSIW surface, two forward passbands have been generated, independently. These two passbands are located below the waveguide cut-off frequency of the dominant mode in the HMSIW structure, which have been designed for WiMAX and WLAN applications. The resonance frequencies of each metamaterial unit cells can be arbitrarily regulated. Accordingly, by resizing the dimensions of each unit cells, the center frequencies of the introduced unit cell could be separately controlled. Four different techniques have been utilized to reduce the size of the proposed devices, which are the evanescent mode technique, HMSIW technique, meander technique, and fractal technique. To illustrate the performance of the proposed structures, the designed dual-band filters (DBFs), and equal DB FPD have been fabricated and measured. A reasonable agreement between simulated and measured results has been achieved. The total size of the proposed HMSIW DBF and FPD is about 0.10 λg × 0.10 λg. The proposed devices have many advantages in terms of compact size, low insertion loss, high selectivity, easy integration with the other planar circuits, and flexible bandwidth allocations.

Compact Dual-Mode Bandpass Filters Based on Half-Mode Substrate-Integrated Waveguide Cavities

This letter presents a novel class of compact dual-mode bandpass filters based on half-mode substrate-integrated waveguide (HMSIW) cavities. By using both TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">102</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">301</sub> modes of the HMSIW rectangular cavity as resonant modes and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> mode as nonresonating mode, a novel HMSIW doublet with two poles and two transmission zeros (TZs) is implemented. The TZs can be located at one side or both sides of the passband. Therefore, flexible responses can be obtained. A two-pole HMSIW filter with asymmetric response and a four-pole HMSIW filter with quasi-elliptic response have been designed, fabricated, and measured, to demonstrate and verify the proposed structure. Compared with substrate-integrated waveguide (SIW) counterparts, the dual-mode HMSIW filters have the advantage of smaller size.

A Bandpass Filter Using Half Mode SIW Structure with Step Impedance Resonator

This paper presents a miniaturized bandpass filter, which uses half mode substrate integrated waveguide (HMSIW) structure with embedded step impedance structure (SIS). By embedding the stepped impedance structure into the top metal of the waveguide cavity, the center frequency can be quickly shifted to a lower frequency. The operating center frequency of the proposed bandpass filter (BPF) using HMSIW resonators with embedded SIS is tunable as functions of the parameters of the SIS. The design curve is provided. A filter example of the center frequency of the filter at 3.5 GHz is fabricated and measured, having the insertion loss |S21| less than 3 dB, and the return loss |S11| greater than 10 dB. The transmission zeros are located at 2.95 GHz and 3.95 GHz on both sides of the passband, both of which are lower than 30 dB. The simulation result and the measured response conform to the proposed design concept. The proposed HMSIW filter design is in line with the current 5G communication trend.

Compact dual‐band filter using interleaved folded half‐mode substrate integrated waveguide resonator

A multi-layer interleaved folded half-mode substrate integrated waveguide (HMSIW) dual-band filter is proposed. The TE 101 and TE 102 mode of the HMSIW resonators form dual-band response by vertical coupling, and the bandwidth of the two passbands can be independently designed by adjusting the coupling apertures. Moreover, three transmission zeros (TZs) are obtained to improve out-of-band rejection, and the TZs can be flexibly designed below or above the passband. By vertically superimposing the HMSIW cavity, the HMSIW filter can be extended to multi-pole dual-band filters. A dual-band filter with centre frequency of 3.05 and 4.7 GHz was fabricated and measured to verify the proposed method. The simulated and measured results are in good agreement.

A novel super compact half‐mode substrate‐integrated waveguide filter using modified complementary split‐ring resonator

A novel super compact filter based on half-mode substrate-integrated waveguide (HMSIW) technology loaded by the modified complementary split-ring resonator (MCSRR) is proposed. The working principle of the proposed filter is based on the evanescent-mode propagation technique. According to this technique, by loading the complementary split-ring resonator (CSRR) on the metal surface of the substrate-integrated waveguide (SIW) structure, an additional passband below the SIW cutoff frequency can be obtained. In order to miniaturize the physical size of the conventional CSRR, a new method is introduced. In the proposed MCSRR unit-cell, the meander slots are carved inside all of the interior space of the ring. Accordingly, the length of the slot is increased which leads to an increase in the inductor and capacitor of the proposed structure without occupying the extra space. Therefore, the electrical size of the proposed MCSRR unit-cell is reduced. Consequently, the resonance frequency of the proposed MCSRR unit-cell is decreased compared to the conventional CSRR with the same sizes. Namely, the lower resonance frequencies can be achieved by using this technique without increasing the size of the unit-cell. In order to confirm the miniaturization technique, two HMSIW filters loaded by the proposed MCSRR unit-cell are designed, fabricated, and experimental verifications are provided. The results show that a miniaturization about 67% is achieved.

Tunable Bandstop HMSIW Filter With Flexible Center Frequency and Bandwidth Using Liquid Crystal

This paper reports on a tunable bandstop filter (BSF) with both flexible center frequency and bandwidth. The tunable BSF is based on half-mode substrate integrated waveguide (HMSIW), of which the broadside is coupled with reconfigurable resonators. Using liquid crystal (LC) material as the substrate, a tunable stopband could be obtained by adjusting the bias voltage of the interdigitated microstrip resonator on LC. In order to increase the tunable range of stopband bandwidth, two additional open resonators are implemented at the broadside of HMSIW cavity. For practical validation, the bandstop HMSIW filter using LC is designed and fabricated. Numerical results demonstrate that,by adjusting the voltages of three resonators on LC, either the lower or the higher cutoff frequency could be controlled independently, leading to the flexible and independent tuning ranges of both center frequency from 4.9 to 5.4 GHz and 3-dB bandwidth of stopband from 1.2 to 1.8 GHz (@5.1 GHz).

Compact Bandstop Half-Mode Substrate Integrated Waveguide Filter Based on a Broadside-Coupled Open Split-Ring Resonator

A shunt RLC resonant circuit obtained from a broadside-coupled open split ring resonator (BC-OSRR) is proposed. This BC-OSRR cell allows a parallel connection with planar waveguides. Hence, it has been applied to a half-mode substrate integrated waveguide (HMSIW) section. The analysis of the frequency response and electromagnetic field distribution of the HMSIW structure loaded with an appropriate BC-OSRR cell have shown two main behaviors. The first characteristic is a high-pass frequency response inherent to the HMSIW and the second is a transmission zero in the passband of the HMSIW, which is due to the resonance of the BC-OSRR cell. The First- and second-order prototypes have been designed and fabricated. The measured bandstop HMSIW filters using BC-OSRR achieve a 3-dB stopband bandwidth around 10% with more than 21-dB insertion loss. This BC-OSRR cell with low undesired radiation loss can be a new alternative for the implementation of compact bandstop filters in the planar technology.

The novel reconfigurable double-layer half-mode SIW filter with tunable DMS structure

ABSTRACTThe contribution of this paper is to present a reconfigurable double-layer half-mode substrate integrated waveguide (HMSIW) bandpass filter with continuous center frequency and 3 dB bandwidth (BW) tuning capabilities. The double-layer rectangular HMSIW is subjected to vertical electrical coupling and magnetic coupling through the proposed semicircle aperture and rectangular slot etched on the middle metal layer. Due to this mixed electric and magnetic coupling structure, the 3 dB BW can be tuned and one adjustable transmission zero (TZ1) is introduced. Varactors (CV2) are used to adjust the center frequency. The parasitic passband produced by the higher-order mode TE102 can be suppressed, thanks to the proposed T-shapes defected microstrip structure. Compared with the conventional horizontal coupling SIW filters, the proposed HMSIW filter also shows a compact physical area. To demonstrate the proposed design method, a double-layer HMSIW bandpass filter is fabricated and measured. Both the simulation and measured results show a center frequency tuning range of 1.21–1.72 GHz, as well as demonstrate a 3 dB BW tuning range of 62–101 MHz around 1.21 GHz, 97–213 MHz around 1.45 GHz, 225–310 MHz around 1.72 GHz. The insertion loss ranges from 1.18 to 6.32 dB. Furthermore, simulated and measured results also show a good agreement.

Extended-Doublet Half-Mode Substrate Integrated Waveguide Bandpass Filter With Wide Stopband

A half-mode substrate integrated waveguide (HSIW) filter incorporated with co-planar waveguide (CPW) and co-planar strip (CPS) is proposed. Quarter-wavelength CPW and half-wavelength CPS resonators etched on the top metal layer are used to realized extended-doublet topology. Meanwhile, wide stopband characteristic is obtained, which is due to different higher order resonant frequencies of HSIW, CPS, and CPW. Finally, an HSIW filter is designed and measured, good agreements are achieved between measured and simulated S-parameters.

Miniaturised ISM band HMSIW band‐pass filter loaded with wide U slot

In this study, two half-mode substrate integrated waveguide (HMSIW) filters are proposed by introducing wide U slot in the conventional SIW (substrate integrated waveguide) structure. In the first case, lower ISM (industrial, scientific and medical radio) band HMSIW filter is designed by extending the centre stub, thereby controlling the resonant frequency and bandwidth. In the second case, higher ISM band HMSIW filter is designed by shorting the extended stub using via. These filters are having a compact core size of 26 mm × 11 mm and work at 2.4 and, 5.8 GHz with a fractional bandwidth of 4.0 and 2.6%, respectively. The filter is fabricated with a single layer standard printed circuit board process. The measured results are good and in agreement with simulated results. The band-pass filter structure has the advantage of low insertion loss, good return loss, sharp side band rejection and compact size.

Miniaturized Slotted Bandpass Filter Design Using a Ridged Half-Mode Substrate Integrated Waveguide

This letter demonstrates significant miniaturization of slotted half-mode substrate integrated waveguide filters by incorporating a capacitive ridge. Based on this concept, two-pole and four-pole slotted bandpass filters are designed, fabricated and measured. Simulations are carried out using HFSS, and the prototypes are fabricated using a multi-layer printed circuit board process. The filters operate at 5.1 and 5.5 GHz and have a total width as small as 5.2 mm. The measured S-parameters of the slotted filters illustrate insertion loss of 0.8 dB and stopbands larger than 8 GHz. Compared to previously reported slotted half-mode substrate integrated waveguide filters, the proposed structure has a smaller footprint, lower insertion loss, and a larger stopband all at once.

Compact half-mode substrate integrated waveguide bandpass filters with capacitively loaded complementary single split ring resonators

A novel compact half-mode substrate integrated waveguide (HMSIW) filter with capacitively loaded complementary single split ring resonators (CSSRRs) is presented in this article.The proposed structure demonstrates lower resonant frequency and enhanced miniaturization compared to the HMSIW with conventional CSSRRs due to the additional capacitance generated by an additional conductor connected to the inner metal disk and overlaid across the ground plane of the CSSRR. Even lower resonant frequency and greater miniaturization can be achieved conveniently by increasing the area of the overlap or using thin dielectric substrate and the technique can readily be realized in a range of multilayer technologies. The equivalent circuit model for the proposed structure of the HMSIW with the capacitively loaded CSSRR is derived and a second-order bandpass filter with the proposed structure, operating at 4.92 GHz, is designed and fabricated. Excellent agreement is achieved between the simulation and the measurement. The proposed HMSIW filter with capacitively loaded CSSRRs shows good selectivity, low loss, and compact size, with the total size being only 9.8 × 7 mm2 (0.17 λ0 × 0.115 λ0) without the feed lines. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1602–1606, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27604

Half mode substrate-integrated waveguide-loaded evanescent-mode bandpass filter

In this article, a filter size reduction of 46% is achieved by reducing a substrate-integrated waveguide (SIW)-loaded evanescent-mode bandpass filter to a half-mode SIW (HMSIW) structure. SIW and HMSIW filters with 1.7 GHz center frequency and 0.2 GHz bandwidth were designed and implemented. Simulation and measurements of the proposed filters utilizing combline resonators have served to prove the underlying principles. SIW and HMSIW filter cavity areas are 11.4 and 6.2 cm2, respectively. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.

Substrate integrated waveguide filters and mechanical/electrical reconfigurable half-mode substrate integrated waveguide filters

In this paper, novel evanescent mode substrate integrated waveguide (SIW) and half-mode substrate integrated waveguide (HMSIW) filters are proposed, and their applications to mechanical and electrical reconfigurable bandpass filters (BPFs) are studied. SIW and HMSIW loaded with coupled complementary split-ring resonators achieve forward electromagnetic wave transmission below the waveguide cutoff frequency due to evanescent wave amplification. The half-mode configuration of the proposed SIW BPF is an opening structure, and the proposed HMSIW BPF is suitable to load with control elements. The electric/magnetic coupling effects and frequency responses reconfigurable mechanics of the proposed HMSIW structure are studied based on lumped equivalent circuit model. By using floating capacitors with mechanical switches and PIN diodes loaded on the HMSIW resonators, two one-bit HMSIW 500 MHz mechanical and 300 MHz electrical reconfigurable BPFs are demonstrated.

Miniaturized Half-Mode Substrate Integrated Waveguide Bandpass Filter Loaded with Double-Sided Complementary Split-Ring Resonators

A novel technique of miniaturizing for a half-mode substrate integrated waveguide bandpass filter by using a double-sided complementary split-ring resonator is presented in this article. With the proposed technique, a double-sided complementary split-ring resonator half-mode substrate integrated waveguide filter provides lower resonance frequency compared to its conventional counterpart because of the coupling effect between the complementary split-ring resonators of the top and bottom plates. The property of the double-sided complementary split-ring resonator is modeled by an LC resonance circuit. The frequency response of the double-sided complementary split-ring resonator shows bandpass characteristics. By applying the classical filter design methodology, the proposed filter was designed for desired filter specifications. Both circuit and full-wave simulated frequency responses have been attributed to the theory of the proposed technique, and good agreement was achieved with experiment results.

출력 단자 간의 격리 특성이 향상된 HMSIW 평형 여파기

In this paper, we propose a half mode substrate integrated waveguide(HMSIW) balanced bandpass filter to yield improved isolation between output ports. In order to achieve good isolation, resistive coupling slot is employed in HMSIW filter. The measurement results show that the insertion losses(, ) are dB and input return loss() is more than 10 dB from 5.8 GHz to 6.4 GHz. Moreover isolation between output ports is larger than 18 dB and phase difference of output ports is .

Half Mode Substrate Integrated Waveguide (HMSIW) Bandpass Filter

This letter presents the design and experiment of the half mode substrate integrated waveguide (HMSIW) bandpass filters. Three-pole and five-pole HMSIW filters are simulated by using CST software and fabricated with a single layer standard printed circuit board process. Different external-coupling approaches are adopted in the design of the two filters. The measured results are in good agreement with the simulated results. Low insertion loss and good selectivity are achieved