A 60 GHz Planar Diplexer Based on Substrate Integrated Waveguide Technology

Normally the physical dimensions of the taper transition that realizes the impedance matching between the impedance of the feeding line built in microstrip line technology and the impedance of the component built in Substrate Integrated Waveguide (SIW) technology are obtained by computational optimization processes due the difficulty of analytical treatment. This research work presents a new empirical approach to determine all the physical dimensions of this particular planar transition without using any computational optimization process. The well-defined design procedure is based on an approximation according with electromagnetic simulations and electromagnetic theory. The main goal is to facilitate the integration between SIW technology and planar circuits. The whole design procedure considers central frequency for the recommended bandwidth in the TE10 propagation mode and power-voltage impedance definition for the SIW. Two structures are designed on RT/duroid 5880 to operate in the X band and Ku band, and the frequency response for both structures are compared by electromagnetic simulation and experimental results. The structure operating in X Band demonstrated return loss better than 10.0 dB at 61.67% of the considered bandwidth and the structure operating in Ku Band demonstrated return loss better than 10.0 dB at 72.88% of the considered bandwidth.

This paper introduces a streamlined design that includes a broadband directional coupler, a set of three-port union-T power dividers, and several microstrip transitions. These components leverage substrate-integrated waveguide (SIW) technology, operating across multiple frequency bands and offering equal power distribution in all output ports. The directional coupler, dividers, and transitions underwent a comprehensive design, simulation, and optimization process using CST Microwave Studio. A crucial aspect of the SIW design was the meticulous consideration of transitions necessary to achieve optimal matching between the SIW devices and the connected structure (such as microstrip or SMA connectors). This approach ensured a consistent focus on seamless integration. For validation purposes, the devices were manufactured physically using the RF-5880 substrate, which works with frequencies up to 40 GHz. The experimental results were then compared with simulations conducted in CST Microwave Studio, validating the prototypes. The findings confirmed that the design performs as intended, exhibiting expected behavior and showcasing a notable agreement between the simulation and experimental results. Furthermore, the designs were treated as standard rectangular waveguides, functioning within microwave and millimeter wave frequencies ranging from 8 to 40 GHz. The paper not only outlines these designs but also proposes practical dimensions for SIW technology, offering a tangible guide for the realization of these devices.

In this summary article, a simple surface wave launcher (SWL) in substrate integrated waveguide (SIW) technology is proposed. The launcher utilizes a conventional microstrip to SIW transition with the motivation of transferring power into the dominant TM 0 surface wave (SW) mode of a grounded dielectric slab (GDS). Moreover, by appropriate design of the SIW section and by applying field matching techniques using sub-wavelength microstrip patches while also conveniently separating some of the via conducting posts for one of the SIW side-walls, power can leak into the GDS with minimal losses for the generation of a bound and guided TM SW with a uniform phase front. The design approach is confirmed by numerical calculations and full-wave simulations for two feed systems which operate at 15 GHz, with and without the matching section. Our new approach for simple, microstrip-fed SW launching at microwave frequencies can also be useful for other SW-based guides, novel low-cost transitions, and new compact dividing/combing circuits for antenna feed systems as well as other SW structures which employ a common substrate.

Substrate Integrated Waveguide (SIW) has been demonstrated for the design of low-cost planar waveguide bandpass filters in the same process as planar circuits. However, SIW cavity resonator generally has a finite Qu of around 500 with most commonly used dielectric substrates, which rounds the passband edge and reduces the effective bandwidth of narrowband filter. In this paper, a K-band bandpass filter with 1 % relative bandwidth and resonators of Qu 500 is synthesized and designed by partial predistortion techniques. The predistorted filter is symmetrically realized by the SIW technology. An effective Qu of about 2500 is obtained and effective bandwidth of the filter is improved. The discrepancy between the actual Qu of SIW cavity resonator and the Qu used by predistortion, as well as the fabrication error lead to the difference between measurement and the simulation results.

The design and realization of a novel wideband two-layer 4 × 4 Butler matrix in substrate integrated waveguide (SIW) technology are addressed. The two-layer SIW design is exploited through a two-fold enhancement approach. The two-layer topology is first explored in a simple matrix layout with minimum number of components. A space saving design is then proposed making optimum use of the two-layer topology and the SIW technology leading to a significant size reduction. A two-level, low-loss, wideband SIW transition is designed and optimized using its equivalent circuit model. The two corresponding Butler matrix prototypes are optimized, fabricated and measured. Measured and simulated results are in good agreement. Isolation characteristics better than -15 dB with input reflection levels lower than - 12 dB are experimentally validated over 24% frequency bandwidth centered at 12.5 GHz. Measured transmission magnitudes and phases exhibit good dispersive characteristics of 1 dB, around an average value of -6.8 dB, and 10° with respect to the theoretical phase values, respectively, over the entire frequency band. The impact of the measured transmission phases and magnitudes on the radiation pattern of a 4-element antenna array is also investigated.

Design of wide band-pass substrate integrated waveguide (SIW) filters based on stepped impedances

Two novel tunable bandstop resonators in substrate integrated waveguide (SIW) technology are presented: a ridged SIW resonator and an open-ended coplanar waveguide (CPW) resonator that is etched into the SIW’s top metallization. The ridged SIW resonator shows a tuning range of 200 MHz at 5.54 GHz. The CPW resonator has a tuning range of 600 MHz at 3.8 GHz. The two bandstop resonators are combined to design a dual-band bandstop filter with one tunable stopband. Measured results confirm that the tunable bandstop circuits presented in this letter can be effectively used in reconfigurable SIW systems.

In this paper, design principles for implementation of broadband T-type and Y-type power divider based on Substrate-Integrated Waveguide (SIW) technology has been presented. Different design curves have been developed based on simulation results and are used to implement 1×2 power dividers of Y-type and T-type. Finally, by cascading T-type and Y-type stages a 1×4 Power divider of equal division is designed and simulated. The proposed design shows a broad bandwidth (-20 dB) of 18.3% and insertion-loss Bandwidth (1%) of 17.86%.

Objectives: In this study, two new power splitters integrated with a novel half mode substrate integrated waveguide (HMSIW) and composite right/left-handed transmission lines (CRLH-TL) cells are presented, realized and compared to a conventional Substrate Integrated Waveguide (SIW) one. Methods: The SIW technology is characterized by a high Q factor and a low return loss, but it suffers from the massive size particularly in low frequencies bands, so to achieve practically 50% miniaturization in size with keeping the high performances of the SIW technique, HMSIW origins from SIW has been utilized. otherwise, so as to reduce the HMSIW device, size, Composite Right/Left-Handed Transmission Lines (CRLH-TL) cells are applied. The designs are printed on a Roger RT/duroid 6010 and performed within an HFSS environment based on the finite element method (FEM). Simulations and measurements of the three power dividers are presented over a frequency band from 2.2 GHz to 2.6 GHz. Findings: The novel proposed component achieves about 70% and 90% of size reduction compared to, respectively, the HMSIW and SIW power splitters. The simulated and measured results are in close agreement. Application: Compared to the SIW power divider and the HMSIW one the novel proposed device is characterized by a compact size and an easy fabrication process. So that it will enable a convenient reduction of size, loss and cost in millimeter-wave and microwave systems.Keywords: Power Divider, HMSIW, SIW, CRLH-TL Cells, Tapered Transition

This paper presents an in-line optimization process for the design of branch-line couplers in Ku-band, using Substrate Integrated Waveguide (SIW) technology with microstrip transitions. This optimization process uses a link between CST Microwave Studio and Matlab, the formulation of objective functions, and the Nelder-Mead optimization algorithm, which made it possible to obtain optimal designs in the waveguide and SIW technology, with couplings around 3 ± 0.88 dB and isolations lower than 20 dB and a phase difference of 90 ± 2° between the output ports, for the frequency band between 14.0 GHz and 16.0 GHz; and all with a reduction of around 14 % of the computation time required when compared with the optimizer of the CST program.

A six-port junction based on substrate integrated waveguide technology with high reliability and efficient performance is proposed in a sub-K-band of 21-23.5 GHz. This substrate integrated waveguide (SIW) six-port junction is constructed from three directional couplers and one T-junction power divider as fundamental components in SIW form, where using appropriate via techniques led to -6 dB coupling coefficients and -15 dB return loss. There is good agreement between the simulation and the measurement results.

In this paper, the research advances on substrate integrated waveguide (SIW) technology and its application in microwave antennas, components and subsystems in the State Key Lab. of Millimeter Waves (SKLMMW) are reviewed, which includes the propagation characteristics and discontinuity analysis of SIW, and its application in the design and implementation of directional antennas, omni-directional antennas, mono-pulse antennas, microwave and millimeter wave filters, directional couplers, power dividers, diplexers, frequency selective surface (FSS), front end and transceivers etc

This work proposes a design of single element and two element antenna array by using SIW (substrate integrated waveguide) technology. SIW techniques provides low cost, small size and convenient integration with planer circuit. Using antenna array enhance the directivity and gain of the proposed antenna. The dimension of proposed antenna is 37 × 45.5mm2 and substrate height is 1.6mm. The proposed antenna structure is designed on FR4 substrate. The dielectric constant of FR4 substrate is 4.3. Using CST microwave studio, simulated results achieved return loss below 10 dB at centre frequency 5.2 GHz, which is very suitable for application of WLAN/WiFi. Enhancement of the directivity and gain of the proposed antenna array is 157.77 % and 160.97 % respectively is achieved.

An integrated millimeter-wave passive front-end based on Substrate Integrated Waveguide (SIW) technology is presented in this research. It consists of a diplexer which acts as channel separator between transmit and receive chains and a common 8×8 SIW slot antenna array for both transmission and reception. Simulation results show very good performance in terms of channel bandwidth, insertion loss, out-of band rejection and channel-to-channel isolation as well as good performance in terms of radiation characteristics at 60 GHz band. The proposed passive front-end can be easily integrated with active components and provide a fully-integrated transceiver front-end adopting the System-on-Substrate concept for millimeter-wave wireless applications.

In this paper, we present a systematic analysis of periodic structures based on substrate integrated waveguide (SIW) technology. In the periodic structures of interest, the unit cell is a circularly-shaped SIW section, which can be extended to any shape. In the beginning, the propagation constants of both even and odd modes of the SIW periodic structures are accurately extracted with the help of a numerical thru-line (TL) calibration technique, which utilizes two periodic structure sections having different cell numbers as calibration standards. Then, two design examples are showcased to validate the analysis results. The first example is a planar crossover structure using the circularly-shaped SIW coupling section. The other is a bandpass filter that is designed by making use of the stopband characteristics of the proposed SIW periodic structures. Good agreement is observed between simulation and measurement for both examples.