Substrate Integrated Waveguide Research Articles

Dual Horn MIMO antenna using SIW technology for mmWave high speed vehicular communication

Abstract The current research investigation proposes solutions for the high speed,
high data rate, reliability and high penetration losses using substrate-integrated waveguide
(SIW) optimized horn antenna technology. A dual horn MIMO antenna with the
cavity holes is designed using multilayer substrates Rogers/Duroid 5880 and Rogers
RO3003 of size 56.31×35.06×1.54 mm3 and it provides wide band frequency range of
26.63 - 35.30 GHz. The critical design parameters and their impact are also included
here. The gain and radiation efficiency in the band are 6.94 - 8.93 dBi and 96.1 %-98%
respectively. The proposed H-plane dual horn MIMO antenna is able to receive signals
in all directions in this research. The ECC is 0-0.002 and the TARC is 8.69 GHz in
the band. The CCL in the band is less than 0.5 as per ITU. The impact of MEG using
isotropic and Gaussian environments and multipath propagation w.r.t.NLOS are also
carried out in this research.

Compact dual-band filter using hybrid transition-free spoof surface plasmon polaritons and substrate integrated waveguide

In this paper, a new hybrid transition-free spoof surface plasmon polaritons (SSPPs)-substrate integrated waveguide(SIW) unit is used to design a compact dual-band filter. Benefiting from the combination of the H-shaped unit and the bilateral T-shaped unit of the proposed hybrid unit, the inherent two-stage wave vector matching is provided to achieve momentum and impedance matching. Thus, the proposed transition-free SSPPs-based filter does not require SSPPs transition units, making the circuit size reduction largely. Moreover, the high-order mode (Mode 1) of the transition-free SSPPs transmission units will not be suppressed by the stopband between the fundamental mode (Mode 0) and Mode 1 of transition-free SSPPs transition unit, making it possible to design a dual-band filter based on Mode 0 and Mode 1. In addition, the cutoff frequency of the filter can be controlled by the geometric size of the hybrid transition-free SSPPs-SIW unit. To verify the design theory, a compact dual-band filter with operating frequencies of 4.4 GHz − 5.6 GHz and 9.0 GHz − 9.6 GHz is designed and fabricated. The simulated results are in good agreement with the test results, indicating the feasibility of the proposed structure and design method.

A Broadband Mode Converter Antenna for Terahertz Communications

The rise of artificial intelligence (AI) necessitates ultra-fast computing, with on-chip terahertz (THz) communication emerging as a key enabler. It offers high bandwidth, low power consumption, dense interconnects, support for multi-core architectures, and 3D circuit integration. However, transitioning between different waveguides remains a major challenge in THz systems. In this paper, we propose a THz band mode converter that converts from a rectangular waveguide (RWG) (WR-0.43) in TE10 mode to a substrate-integrated waveguide (SIW) in TE20 mode. The converter comprises a tapered waveguide, a widened waveguide, a zigzag antenna, and an aperture coupling slot. The zigzag antenna effectively captures the electromagnetic (EM) energy from the RWG, which is then coupled to the aperture slot. This coupling generates a quasi-slotline mode for the electric field (E-field) along the longitudinal side of the aperture, exhibiting odd symmetry akin to the SIW’s TE20 mode. Consequently, the TE20 mode is excited in the symmetrical plane of the SIW and propagates transversely. Our work details the mode transition principle through simulations of the EM field distribution and model optimization. A back-to-back RWG TE10-to-TE10 mode converter is designed, demonstrating an insertion loss of approximately 5 dB over the wide frequency range band of 2.15–2.36 THz, showing a return loss of 10 dB. An on-chip antenna is proposed which is fed by a single higher-order mode of the SIW, achieving a maximum gain of 4.49 dB. Furthermore, a balun based on the proposed converter is designed, confirming the presence of the TE20 mode in the SIW. The proposed mode converter demonstrates its feasibility for integration into a THz-band high-speed circuit due to its efficient mode conversion and compact planar design.

Design of compact microstrip high gain filtering antenna array based on SIW cavity

ABSTRACT The article has designed a single-mode, substrate-integrated waveguide (SIW), high-gain filtering array antenna. The proposed filtering antenna array is implemented on a stack of metal and dielectric substrate layers with SIW cavity and CPW feeding at the bottom layer to excite the single T E 201 mode. It acts as the first stage of the filter resonator, facilitating the four-way power distribution through the slots to the 2 × 2circular patch array acting as the second stage of the filtering resonator. With the advantages of the reutilisation of the existing high-order SIW cavities, the presented filtering array antenna offers low loss, very high gain, high efficiency, miniaturised size, and simple construction. A filtering array prototype with dimensions 1.081 λ x0.752 λ x0.023 λ has been fabricated using a multi-layer printed circuit board method and measured to validate the proposed design.The structure offers a peak gain of 12.6 dBi, fractional bandwidth (FBW) of 4.6%, and 96% peak radiation efficiency at the centre frequency of 13.68 GHz. An excellent correlation is observed between the measured and simulation results. The proposed design has immense potential in high-frequency and wide-ranging filtering arrays for radar and satellite in Ku band applications.

A single/dual band frequency switchable antenna based on SIW for UAV detection applications

ABSTRACT In this paper, we propose a substrate-integrated waveguide (SIW) antenna with frequency switching capabilities for unmanned aerial vehicle (UAV) detection applications. This antenna features a T-shaped slot on its top surface that excites the quarter-TE110 mode to extend its bandwidth. Based on this configuration, three PIN diodes connect the T-shaped patch to the top metal layer, enabling the antenna to switch frequencies dynamically by adjusting the states of these diodes. Experimental results demonstrate that when the three PIN diodes are in the OFF state, the antenna achieves bandwidths of 12.79% and 0.92% in the X-band and Ku-band, respectively. Conversely, when the diodes are turned ON, the antenna operates in the X-band with a bandwidth of 2.6%. Consequently, this antenna successfully facilitates dynamic frequency switching between the X-band and Ku-band. The maximum gains in these three operating bands are 6.6dBi, 3.5dBi, and 5.4dBi, respectively.

Dual Band Modified Complementary Split Ring Resonator Loaded Substrate Integrated Waveguide Based Bandpass Filter

This study presents a dual-band bandpass filter design that implements microstrip to substrate integrated waveguide (SIW) transition to decrease radiation losses. The proposed filter is designed with using four complementary split ring resonators (CSRR) to minimize its size and to gain double negative property. A bowtie shaped slot is etched inside CSRR to have a second resonance at the spectrum. After the simulation results are performed the designed filter is fabricated on a Rogers RT5880 dielectric substrate and the experimental results are compared with the simulation results. The proposed filter has center frequencies at 6.57 and 12.55 GHz with fractional bandwidth (FBW) of 22.05% and 26.29%, respectively. Moreover, the presented filter offers the best bandwidth-to-size result with the size of 0.327λg×0.352λg (where λg is the wavelength at the first passband’s center frequency).

Broadband HMSIW antenna using a demi hexagonal ring slot for X-band application

Microstrip antennas offer several advantages, including small size, easy fabrication, controllable polarity and radiation patterns, and easy integration with other components. These qualities make microstrip antennas more reliable than other antenna types. However, they also have limitations, such as lower radiation efficiency and narrow bandwidth, primarily due to the thin substrate thickness. Substrate integrated waveguide (SIW) is a type of microstrip antenna. SIW antennas come in two forms: one with a rectangular shape, typically designed as a slot, and the other in the form of a horn. However, SIW slot antennas face challenges with narrow impedance bandwidth due to the thin substrate, unlike conventional bulky hollow waveguides. The half-mode substrate integrated waveguide (HMSIW) slot antenna, which is a 50% miniaturized version of the SIW slot antenna, also suffers from reduced fractional bandwidth, resulting from the miniaturization and the thin substrate. This paper focuses on enhancing the bandwidth of HMSIW antennas by incorporating a demi-hexagonal ring slot. The broadband impedance bandwidth simulation (27.36%) is achieved through triple resonance frequencies to address the issue of narrow impedance bandwidth. Both the simulation results and measurements show consistency, with the measured impedance bandwidth ranging from 8.91 to 12.62 GHz (34.46%), demonstrating at least triple resonance frequencies.

패치 구조를 이용한 D-Band(140 GHz - 160 GHz) 대역 도파관-마이크로스트립 변환기의 광대역 설계

This paper presents the design of a waveguide-to-microstrip transition for millimeter-wave integrated circuits that fulfills the requirements of the D-band (140 GHz-160 GHz). The proposed transition is vertically structured to minimize loss, transferring signals that propagate from a WR-7 standard waveguide to a microstrip via a substrate integrated waveguide (SIW). To enable efficient mode conversion, a patch is inserted between the standard waveguide and SIW. Using HFSS from Ansoft, the frequency characteristics were analyzed by adjusting the patch size and position of the pin, achieving a wideband design. The substrate used for the design is Taconic RF-35, with a dielectric constant of 3.5 (loss tangent 0.0018) and a thickness of 0.254 mm. Simulation results demonstrate a bandwidth from 124 GHz to 163 GHz, with an average insertion loss of -0.9 dB or less and an average return loss of -10 dB or less across the band.

Substrate Integrated Waveguide on Glass with Vacuum-Filled Tin Through Glass Vias for Millimeter-Wave Applications.

This paper presents a novel approach to fabricate substrate integrated waveguides (SIWs) on glass substrates with tin (Sn) through glass vias (TGVs) tailored for millimeter-wave applications. The fabrication process employs a custom-designed vacuum suctioning system to rapidly fill precise TGV holes in the glass substrate, which are formed by wafer-level glass reflow micromachining techniques with molten tin in a minute. This method offers a very fast and cost-effective alternative for complete via filling without voids compared to the conventional metallization techniques such as electroplating or sputtering. An SIW with a 3-dB cutoff frequency of 17.2 GHz was fabricated using the proposed process. The fabricated SIW shows an average insertion loss of 1.65 ± 0.54 dB across the 20-35 GHz range. These results highlight the potential of glass substrates with tin TGVs for fabricating millimeter-wave devices.

A 8 GHz microwave substrate integrated waveguide power amplifier using complementary split ring resonators

This paper introduces a design for a microwave substrate integrated waveguide (SIW) power amplifier (PA) for modern wireless communications. The amplifier design incorporates complementary split ring resonator (CSRR) structures integrated within the SIW to achieve low-loss characteristics and miniaturization through a below cut-off frequency operation approach. The designed PA operates at 8 GHz and exhibits good performance, which are measured output power Pout of 35.51 dBm, a maximum power added efficiency PAE of 47.2% and a power gain of 12.51 dB. The final circuit occupies just a compact size of 41 x 15.7 mm2 benefiting from using the CSRR structure. The proposed PA employs a low-cost QFN packaged GaN HEMT device from Qorvo and it was designed and fabricated on a cost-effective RO4003C substrate. The simulated results agree well with the measured ones validating the accuracy of the design. With promising measured results, the proposed PA can be a potential candidate for using in the modern wireless communication systems.

Design and SAR Analysis of an AMC-Integrated Wearable Cavity-Backed SIW Antenna.

Wearable communication technologies necessitate antenna designs that harmonize ergonomic compatibility, reliable performance, and minimal interaction with human tissues. However, high specific absorption rate (SAR) levels, limited radiation efficiency, and challenges in integration with flexible materials have significantly constrained widespread deployment. To address these limitations, this manuscript introduces a novel wearable cavity-backed substrate-integrated waveguide (SIW) antenna augmented with artificial magnetic conductor (AMC) structures. The proposed architecture is meticulously engineered using diverse textile substrates, including cotton, jeans, and jute, to synergistically integrate SIW and AMC technologies, mitigating body-induced performance degradation while ensuring safety and high radiation efficiency. The proposed design demonstrates significant performance enhancements, achieving SAR reductions to 0.672 W/kg on the spine and 0.341 W/kg on the forelimb for the cotton substrate. Furthermore, the AMC-backed implementation attains ultra-low reflection coefficients, as low as -26.56 dB, alongside a gain improvement of up to 1.37 dB, culminating in a total gain of 7.09 dBi. The impedance bandwidth exceeds the ISM band specifications, spanning 150 MHz (2.3-2.45 GHz). The design maintains remarkable resilience and operational stability under varying conditions, including dynamic bending and proximity to human body models. By substantially suppressing back radiation, enhancing directional gain, and preserving impedance matching, the AMC integration optimally adapts the antenna to body-centric communication scenarios. This study uniquely investigates the dielectric and mechanical properties of textile substrates within the AMC-SIW configuration, emphasizing their practicality for wearable applications. This research sets a precedent for wearable antenna innovation, achieving an unprecedented balance of flexibility, safety, and electromagnetic performance while establishing a foundation for next-generation wearable systems.

A D-Band Dual-Polarized High-Gain LTCC-Based Reflectarray Antenna Using SIW Magnetoelectric-Dipole Elements.

This paper presents a D-band dual linear-polarized wideband high-gain reflectarray (RA) antenna using low-temperature co-fired-ceramic (LTCC) technology. The proposed element comprises a dual-polarized magnetoelectric (ME) dipole and a multilayer slot-coupling substrate-integrated waveguide (SIW) phase-delay structure, which are organized in accordance with the receiving/reradiating (R/R) principle. The coverage of phase shifts for both orthogonal polarizations is set to be greater than 360 degrees by varying the length of the phase-delay structure. For verification, a D-band 1296-element RA prototype using the proposed unit cell is fabricated and measured in a THz chamber. The measured results show that the proposed RA achieves a peak gain of 32.25 and 33.03 dBi for the two orthogonal polarizations. The measured 3 dB gain bandwidths for the two orthogonal polarizations are 122-149 GHz (20%) and 123-149 GHz (19.3%), respectively.

A compact self-quintuplexing antenna by HM-SIW cavity

Abstract This paper presents a novel compact self-quintuplexing antenna using a half-mode substrate-integrated waveguide cavity to implement multi-operation wireless services. The proposed antenna design incorporates five triangular protrusions of different dimensions, assembled with SIW to function as the radiating elements. Each radiator supports the one-eighth mode of the SIW cavity. The resonance frequencies of radiators are 3.63, 4.44, 5.23, 6.21, and 7.05 GHz. Each radiator operates at a distinct frequency due to the differing dimensions and is independently driven by 50 Ω microstrip lines. The measured reflection coefficients and isolation among any two ports are less than −10 dB and better than 23.6 dB, respectively. The measured gains at their respective resonant frequencies are 5.66, 4.84, 5.03, 7.08, and 6.59 dBi. The front-to-back ratio is better than 8.7 dB in each band. The difference of co-to-cross-polarization is greater than 19.3 dB.

A broadband substrate integrated waveguide fed dielectric resonator antenna with U-slot for 5G-NR Band

Abstract In the proposed design, a Substrate Integrated Waveguide (SIW) feeding mechanism is utilized in conjunction with a higher-order mode Dielectric Resonator Antenna (DRA), which is excited by a U-slot aperture on the top side of the ground plane. This structure is aimed for 5G millimeter-wave bands, N257, and N258. Both sides of SIW are clad with 0.035mm copper with a permittivity of 2.2, Rogers 5880 is used as substrate. In contrast, DRA has a permittivity of 10. The design achieves a notable impedance bandwidth of 25-31.12 GHz (6.12 GHz or 21.8%) due to the excitation of multiple resonances of DRA modes. It delivers high gain values of 8.5 dBi at 25.8 GHz, 8.9 dBi at 27.5 GHz, and 7.2 dBi at 30 GHz, with radiation efficiency exceeding 98% within the resonance band. The radiation patterns demonstrate good co-polarized performance, validating the broadside transmission. All simulations were conducted using Ansys HFSS version 2023.

High-Order Resonating Cavity-Backed Slot Antenna Array Based on Contactless Air-Filled Substrate-Integrated Waveguide and Transition to Inverted Grounded Coplanar Gap Waveguide

High-Order Resonating Cavity-Backed Slot Antenna Array Based on Contactless Air-Filled Substrate-Integrated Waveguide and Transition to Inverted Grounded Coplanar Gap Waveguide

A wideband circularly polarized filtering dielectric resonator antenna array based on magneto-electric currents combination

ABSTRACT A circularly polarized (CP) filtering dielectric resonator antenna (DRA) array is proposed based on the magneto-electric currents combination (MECC) method in this paper. The array consists of four rectangular DRAs, four hook-shaped electric dipoles (HSED), and two layers of substrate integrated waveguide (SIW) cavities. The electric current (EC) on the HSED is excited by the slot aperture of the SIW cavity, and the equivalent magnetic current (MC) is simultaneously generated with HSED in the DRA. Based on the surface current regulation, the EC and MC are adjusted to achieve appropriate amplitudes and phases, thereby realizing wideband CP radiation. The filtering function is realized with the high-pass characteristics of the SIW and the effective suppression of the higher-order modes in the resonance cavity. Due to the presence of an air gap between the DRAs and HSED, the higher modes of the DRA are designed for bandwidth enhancement. The prototype of the DRA array has been fabricated and measured, exhibiting a relative bandwidth of 26.1% and an axial ratio bandwidth of 17.77%, with radiation nulls present at either side of the passband. With the advantages of wide bandwidth and high gain, the proposed DRA array can be applied to satellite communications.

Design of a Half-Mode Substrate-Integrated Waveguide (HMSIW) Multimode Resonator Bandpass Filter Using the Minkowski Fractal for C-Band Applications.

A substrate-integrated waveguide (SIW) bandpass filter (BPF) with extraordinary selectivity and an adequate upper stopband for C-band Satellite Communication (SATCOM) applications is proposed in this paper. The design comprises comb-shaped slots engraved on a half-mode SIW (HMSIW) that constitute a multimode resonator (MMR). Its performance is further ameliorated by applying the first and second iterations of the Minkowski fractal curve in the ground plane as a defected ground structure (DGS). The Minkowski fractal has advantages in terms of better bandwidth and miniaturization. The filter is first simulated using the commercial full-wave electromagnetic simulator HFSS v19 and then fabricated on a 0.062'' (1.6 mm) FR4 with dielectric constant εr = 4.4. The measured results are comparable with the simulated ones and demonstrate that the BPF has a resonant frequency (f0) of 4.75 GHz, a 3 dB bandwidth of 770 MHz (fractional bandwidth of 21.4%), an insertion loss of 1.05 dB, and an out-of-band rejection (in the stopband) of more than 28 dB up to 8 GHz, demonstrating a wide and deep stopband. Using the multimode resonator (MMR) technique, a wide bandwidth has been achieved, and by virtue of using half-mode SIW (HMSIW), the proposed BPF is compact in size. Also, the fractal DGS aids in better stopband performance.

Compact and Wide-Stopband Bandpass Filter Using Hybrid Shielded EMCSIW and CSRR Resonators with a Mixed Electromagnetic Coupling Scheme.

This paper presents a bandpass filter (BPF) exploiting hybrid shielded eighth-mode circular substrate-integrated waveguide (SD-EMCSIW) and complementary split ring resonator (CSRR) resonators. The proposed BPF leverages the SD-EMCSIW resonator with a 45-degree angle to create a second-order BPF with a mixed electromagnetic coupling scheme. Detailed analyses of the related electromagnetic characteristics and operating mechanisms have been performed. In order to further reduce the occupied area, the CSRR structures are embedded into the SD-EMCSIW resonators. Meanwhile, extra metallic via-holes are implemented to enhance the upper-stopband performance. A transmission zero (TZ) of the second-order BPF can be placed on either the left or right side of the passband and can be flexibly adjusted. To validate the design concept, a second-order hybrid SD-EMCSIW and CSRR BPF was designed, simulated, fabricated, and measured as a specific example. The prototype operates at a center frequency f0 of 8.3 GHz with a 3 dB fractional bandwidth of 8.1%. Two transmission zeros are located near the right passband. The upper-stopband rejection reaches up to 15 dB at 2.85 times the center frequency f0. Both the simulated and measured results show satisfactory agreement. Meanwhile, the overall size of the proposed hybrid SD-EMCSIW and CSRR BPF is 13.5 mm × 13.0 mm (0.37λ0 × 0.36λ0), featuring a compact physical dimension in the filter design.

Substrate integrated waveguide differential antenna for full duplex applications

Abstract This paper presents a substrate-integrated waveguide (SIW) differential antenna for full duplex applications. The proposed antenna consists of two square SIW cavities named as outer and inner. The inner cavity is nested into the outer cavity. The outer cavity is differentially excited with a pair of coaxial feed lines, while the inner square patch is orthogonally excited with another pair of differential coaxial feed lines. This orthogonal feeding arrangement results in high isolation between the differential ports. The modified hybrid TE130/310 mode of the outer cavity radiates through a pair of arc-shaped slots at 9.35 GHz, while the TM01 mode of the inner square patch is responsible for the radiations at 8.65 GHz. The proposed antenna prototype is fabricated and measured for validation. Moreover, the designed antenna has a front-to-back ratio better than 22 dB and measured maximum gain values of 6.1 dBi and 7.6 dBi at 8.65 GHz (Port 2 ON) and 9.35 GHz (Port 1 ON), respectively.

Multilayer substrate integrated waveguide six-port junctions with embedded resistive films

Abstract This article deals with multilayer substrate integrated waveguide (SIW) six-port junctions with embedded carbon resistive films. SIW six-ports usually employ reactive power dividers, which degrade the amplitude and phase balance when the six-port is terminated with mismatched power detectors. The associated impairments are studied and two SIW six-port junctions with improved isolation and output matching are designed for K-/Ka-band applications to overcome these limitations. The proposed designs differ with respect to the configuration of the output ports making the underlying six-port topology applicable for different layout requirements. Measurements of the fabricated components validate the concept. The six-ports are compact, fully shielded and can be integrated in multilayer printed circuit boards.