Corrugated Substrate Integrated Waveguide Research Articles

Dual-Band Large-Frequency Ratio Power Divider Using Mode Composite Transmission Line for 5G Communication Systems

In this paper, a novel kind of mode composite transmission line (MC-TL) is proposed, and a dual-band power divider with a large frequency ratio using this novel MC-TL for 5G communication systems was developed. The proposed MC-TL was developed using spoof surface plasmon polaritons (SSPPs) and a corrugated substrate-integrated waveguide (CSIW) transmission line, which supports both a surface plasmon mode and TE10 mode, independently. The surface plasmon mode operates in the grooves of the surface metal layer, while the TE10 mode works in the substrate between two metal layers. These two parts can transmit different modes at independent frequencies. This structure can be used in dual-band transmission lines with a high frequency ratio. The characteristics and design of the MC-TL (SSPPs and CSIW) are analyzed and illustrated. The MC-TL was fabricated and measured to demonstrate its performance. Moreover, based on the proposed MC-TL, a dual-band power divider with a large frequency ratio (operating at 3 GHz and 28 GHz simultaneously) was also designed and fabricated. It can cover the frequency of a fifth-generation communication system perfectly. The measured outcomes align closely with the simulated results, demonstrating robust agreement and showcasing excellent transmission capabilities.

Full 360° beam steering millimetre‐wave leaky‐wave antennas coupled with bespoke 3D‐printed dielectric lenses for 5G base stations

AbstractA fast beam‐steering capability has been demonstrated using an array of high‐gain corrugated substrate integrated waveguide (CSIW) slot antennas coupled with a bespoke dielectric lens. The proposed system prototype has been simulated, fabricated, and measured. The proposed system is shown to have a full 360° beam‐steer in azimuth plane with an angular sensitivity of 9°, half power beamwidth (HPBW) of 18° and a gain of < 20.5 dBi at n257 frequency band of 26 to 29 GHz. Further, the antenna is shown to have a fixed frequency beam steer of ±15° along with a frequency‐controlled beam‐scanning of ±45° in the elevation plane. The antenna setup is shown to be suitable for applications for 5G base‐stations.

Compact Microstrip Line to Rectangular Waveguide Transition Using Corrugated Substrate Integrated Waveguide

To meet the packaging requirements of terahertz (THz) communication systems, a microstrip line (MSL) to rectangular waveguide (RWG) transition is proposed in this paper. In the transition, the MSL is connected to the corrugated substrate integrated waveguide (CSIW) by a tapered MSL for quasi-TEM to TE10-like mode conversion on substrate, which requires no via holes or shaped dielectric, and is easy to process in THz bands. Then, the CSIW is straightly connected to the RWG transformer and converted to standard RWG, resulting in a compact structure. The working principle of the proposed transition is analyzed, and the influence of several important parameters on the S-parameters of the transition is discussed. A single transition is designed for the 325–500 GHz operation, the S11 better than −14.5 dB and S21 better than −1.03 dB have been achieved in the entire frequency band.

Millimeter-Wave Beam Steerable Slot Array Antenna Using an Inter-Digitated Capacitor Based Corrugated SIW

A new class of electronically beam-steerable corrugated substrate integrated waveguide (CSIW) slot array antenna operating at 26–29 GHz has been developed. The conventional via-based walls of substrate integrated waveguides (SIWs) or stub-based walls of CSIWs have been replaced with an interdigitated capacitor (IDC) structure to enable reconfigurability. This novel IDC-CSIW is shown to have a lower transmission loss compared with conventional CSIWs in the literature. A new mathematical method has been described to calculate the cutoff frequency of IDC-CSIWs. The surface of the IDC-CSIW is then loaded with longitudinal slots, building a leaky-wave architecture. Radiation from individual slots is controlled by shorting the IDC at specific points using p-i-n diodes. The antenna is fed at either end using a single-pole–double-throw (SPDT) switch to achieve a 2-D reconfigurable beam. A compact switched array of two IDC-CSIWs is demonstrated to produce a continuous full sector coverage of 120° in the azimuth plane and ±15° in the elevation plane, providing a 2-D beam steer with a stable gain of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 13.5$ </tex-math></inline-formula> dBi and an efficiency greater than 80%.

Angular Displacement Sensor Based on Corrugated Substrate Integrated Waveguide (CSIW)

An angular displacement sensor is designed using a corrugated substrate integrated waveguide (CSIW) cavity resonator. In the proposed cavity, instead of copper vias, one of the electric walls is made by a number of open quarter guided wavelength stubs and to make an angular displacement sensor, a rotatable copper sheet is located on the stubs. When the copper sheet rotates, the length of the stubs varies causing the shift of the resonant frequency. This relation between the variation of the rotation of the sheet and the resonant frequency shift is represented by an analytical model. According to the result of the measurement and that obtained by analytical model there is a good agreement between them, in addition the results indicate that the sensor provides an angle range of 21° and a sensitivity of 11.3 MHz/degree.

Design of Compact Multilayer Differential CSIW and HMCSIW With High Common-Mode Suppression

In this letter, the compact multilayer differential corrugated substrate integrated waveguide (CSIW) and half-mode CSIW (HMCSIW) are designed by two vertically stacked identical CSIW and HMCSIW, respectively, and an aperture is etched on the common ground between them. Both the CSIW and HMCSIW have only one nonzero vertical electric field component in host waveguide. Under the common-mode (CM) operation, the aperture is a perfect magnetic conductor (PMC). When the height of the single substrate is less than $\lambda _{g}$ /4, the space between the perfect electric conductor (PEC) and PMC cannot transmit electromagnetic waves, and the edge of the aperture is an open circuit. Therefore, the etched aperture in differential CSIW can effectively cutoff CM noise. For the HMCSIW, the spoof surface plasmon polariton (SPP) is loaded in the aperture near the open circuit plane to suppress the slot line mode. Under the differential-mode (DM) operation, the aperture has less effect on the DM frequency responses. For verification, the differential HMCSIW is fabricated, and good agreement between the measured and simulated results demonstrates the validity of proposed configurations.

High sensitivity simple structured displacement sensor using corrugated substrate‐integrated waveguide (CSIW)

In this study, a corrugated substrate-integrated waveguide (CSIW) is used to design a passive microwave displacement sensor. Hence, one of the electric walls of the proposed structure is formed by open-circuited quarter guided wavelength stubs and the other walls are made by metal vias and moveable copper metal is placed on the stubs. By displacing the moveable metal layer along with the stubs, the length of the stubs is changed and therefore the resonant frequency is shifted. An analytical model that relates the variation of the resonant frequency and the displacement has been formulated. The proposed sensor seems like a simple structure and it is operated at 2.4-2.9 GHz. There is a good agreement between the measured results and those obtained by simulation. The measured results indicate that the sensor provides a high dynamic range of displacement of 15 mm and high sensitivity of 25.16 MHz/mm.

A Broadband High-Gain Circularly Polarized Wide Beam Scanning Leaky-Wave Antenna

A new type of broadband circularly polarized leaky-wave antenna (LWA) with high-gain based on a corrugated substrate integrated waveguide (CSIW) structure is proposed and investigated. The CSIW structure that employs open-circuit stubs to replace metallic vias has the advantages of low-cost and easy fabrication as compared to conventional substrate integrated waveguides. Each unit-cell of the proposed LWA consists of two quarter-wavelength microstrip lines and a half-mode CSIW cell with three open-circuit stubs. Two M-shaped slots etched on the half-mode CSIW cell enables the generation of circularly polarized (CP) radiation. The full LWA, which consists of thirteen matched unit-cells cascaded along the direction of propagation enables continuous backward to forward beam scanning. The properties of the CSIW structure, including impedance matching and phase constant, are analyzed by Bloch impedance and dispersion simulations and the influence of the dimensions of the open-circuit stubs on the CP LWA performance is also investigated. A protype of the proposed LWA is fabricated and characterized. The measured results indicate that the proposed CSIW LWA has a high peak gain (9.3-12.5 dBi) throughout a large beam-scanning angle range from -28° to +25°, and the impedance bandwidth and 3-dB axial ratio (AR) bandwidth are over 40% covering the full $\textit {Ka}$ -band.

An Electronically Controlled Leaky-Wave Antenna Based on Corrugated SIW Structure With Fixed-Frequency Beam Scanning

A novel electronically controlled (EC) leaky-wave antenna (LWA) based on corrugated substrate integrated waveguide (CSIW) with fixed-frequency beam-steerable capability is presented in this letter. This structure is based on a CSIW structure with rectangular ring slots and metallic vias to the ground, which realizes two isolated dc equipotential planes. Each slot of the rectangular ring is loaded with a varactor diode, and thus the series and shunt capacitance are tunable by adjusting the dc bias voltage, which eventually results in beam scanning at a fixed frequency. The proposed antenna is a single-layer structure and has a simplified dc bias network, which merely needs an inductor and a short microstrip line. An EC beam-steerable CSIW LWA is designed and experimentally validated. It is experimentally demonstrated that the radiation angle ranges from −40.66° to 31.32° as the bias voltage is tuned from 32 V to 7.5 V at 4.5 GHz.

Tunable Microwave Bandpass Filters With Complementary Split Ring Resonator and Liquid Crystal Materials

In this paper, a novel planar waveguide filter based on liquid crystal materials is devised, and a half-mode corrugated substrate integrated waveguide (HMCSIW) tunable bandpass filter with complementary split ring resonator (CSRR) structure is proposed. The HMCSIW uses an array of quarter-wave open-circuit stubs to replace conventional substrate integrated waveguide (SIW). While retaining the original cut-off frequency of corrugated substrate integrated waveguide (CSIW), we reduce the circuit size by splitting the central axis to achieve the miniaturization. By utilizing band-stop features of the CSRR in microstrip structure and combining with the electronically controlled dielectric constant of liquid crystal materials with high modulation efficiency of inverted microstrip line structure, a CSRR-loaded HMCSIW bandpass filter with liquid crystal materials is implemented. The experimental results demonstrate that the center frequency of the new filter can be adjusted in a range of 0.65 GHz, the pass-band insertion loss is less than 3.4 dB, the return loss is less than -10 dB, and the structure size is 32 mm $\times \,\, 76$ mm, which verify that the designed tunable band-pass filter achieves good frequency selection performance.

A Novel Frequency Scanning Leaky-Wave Antenna Based on Corrugated Substrate Integrated Waveguide

In order to facilitate the integration of active devices, a leaky-wave antenna (LWA) based on corrugated substrate integrated waveguide (CSIW) structure is proposed. By introducing rectangular ring slots on the CSIW structure, the proposed LWA is capable of beam scanning from backward to forward. The rectangular ring slots do not only enable energy leaking but also provide series capacitance. In addition, the grounded vias and quarter-wave open-circuit stubs provide shunt inductance. Thus, the proposed CSIW exhibits left-handed characteristic which enables beam scanning through the broadside. To further facilitate the design and suppress open-stopband of beam scanning antenna based on CSIW structure, an equivalent circuit model is developed and the relationships between structure parameters and the equivalent circuit parameters are presented. Based on this design guide, a leaky wave antenna is designed with radiation angle ranging from −53° to 23°. This proposed novel CSIW LWA has great potential in tunable or reconfigurable antenna design due to its ease of integration with active devices.

Design and Analysis of 150° Bend SIW and Corrugated SIW Bandpass Filter with Multiple Transmission Zeroes Using Reactive Periodic Structures Suitable for Microwave Integrated Circuits (MICs)

Microwave multi-band bandpass filter using substrate integrated waveguide (SIW) and corrugated SIW (CSIW) over Neltec NH9320 with dielectric constant of 3.2, thickness 30 mil and loss tangent tanδ = 0.0024 are presented in this paper. Firstly, 150° bend in the SIW BPF has been provided in SIW multi-band filters in view of its overall size reduction compared to planar un-bend structures and integration ability as required in microwave integrated circuits. Secondly, Reactive periodic slots are introduced over the SIW surface to obtain multiple transmission zeroes within the passband. These slots are bend to 150° in alignment to the 150° bend within the waveguide section. The method presented is further extended for designing CSIW multi-band BPF. Impacts of several parameters of the periodic slots (which are also 150° bend in accordance with the SIW structure) are analyzed. The measured results ensure improved filter performance like low reflection as well as improved isolation. The angular bend used in the BPF enables it to be integrated with other planar circuits within the same PCB material. Passbands obtained within the microwave Ku-bands are suitable for use in Direct Broadcasting Satellite communication systems.

H-plane horn antenna using corrugated substrate integrated waveguide

In this paper, a novel corrugated substrate integrated waveguide (CSIW)-based H-plane horn antenna has been proposed for X-band applications. Quarter-wavelength open-circuited microstrip stubs are used in CSIW structures to achieve the TE10-like boundary condition. This structure does not require any conducting vias such as conventional substrate integrated waveguide (SIW). The antenna is fed by taper microstrip line followed by a section of CSIW operating in TE10 mode. The last section is flared section which is responsible for radiation from the structure. The structure is simulated with ANSYS made HFSS software, and a prototype is fabricated. The measurement results show an impedance bandwidth of 17.2% covering from 8.4 to 10.1 GHz. The radiation pattern is stable over the entire band of operation and has a peak gain of 12.5 dBi. The simulation results are in good agreement with the measured values.

Numerical de‐embedding and experimental validation of propagation properties of corrugated substrate integrated waveguide

ABSTRACTIn this article, a corrugated substrate integrated waveguide (CSIW) with no metallic vias is proposed, and its propagation characteristics are theoretically investigated via our numerical short‐open calibration (SOC) de‐embedding method. In our analysis, dominant operating modes in this CSIW at different frequencies are extensively discussed. Its complex propagation constant is derived to demonstrate its frequency‐dispersive transmission and attenuation performance. Then, the design rules are described to analyze and design CSIW line. In final, the fabricated CSIW with the microstrip‐line feeders are measured to validate the numerically de‐embedded attenuation constant over a wide frequency range. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2456–2460, 2016

직류 전원 공급이 가능한 Folded Corrugated SIW

기판 집적 도파관(SIW: Substrate Integrated Waveguide)는 양면 도체 기판과 도체 비아를 사용하여 매우 얇은 구형 도파관을 형성하는 것으로 사용되는 도체 모두가 직류적으로 하나로 연결되어 있어서 직류 전원 공급이 불가능하다. 본 논문에서는 직류 전원 공급이 가능한 folded corrugated substrate integrated waveguide(FCSIW)를 제안한다. 제안된 FCSIW는 SIW에 사용되는 전도성 비아를 구부러진 형태의 개방형 스터브로 대체하여 직류 전원 공급이 가능하다. 이 FCSIW는 기존의 직류 전원 공급이 가능한 corrugated substrate integrated waveguide (CSIW)에서 나타나는 누설파 발생이 없어서 광대역 전송 특성이 우수하고, CSIW에 비하여 전송선의 단면 폭을 30 % 줄일 수 있다. 9~15 GHz 대역에서 측정된 154 mm 길이의 FCSIW의 평균 삽입 손실(1.49 dB)이 CSIW의 값(3.08 dB)에 비하여 매우 우수함을 확인하였으며, 상호 간섭 측정으로부터 누설파가 발생되지 않음을 확인하였다. Substrate integrated waveguide(SIW) constructed by two metal planes and conductive vias in a dielectric substrate, have all the conductors connected each other and hence, cannot be biased by DC sources. We propose a new folded corrugated substrate integrated waveguide(FCSIW) that can be DC-biased. Since the proposed FCSIW replaces the SIW conducting vias by folded open subs, it can supply the DC sources. The FCSIW has better transmission characteristics and 30 % less width than the common corrugated substrate integrated waveguide(CSIW) having a serious leakage generation problem. The FCSIW shows better insertion loss(1.49 dB) compared with that(3.08 dB) of the CSIW measured for 154 mm length devices and averaged at 9~15 GHz frequency band. No leakage has been observed from crosstalk measurements of the FCSIW.

Folded Corrugated SIW (FCSIW) Slot Antenna for Backlobe Suppression

A novel substrate integrated waveguide (SIW) slot antenna having folded corrugated stubs is proposed for suppressing the backlobes of the SIW slot antenna associated with the diffraction of the spillover current. The longitudinal array of the folded stubs replacing the SIW via-holes effectively prevents the propagation of the surface spillover current. The measured front-to-back ratio (FTBR) has been greatly (15 dB) improved from that of the common SIW slot antenna. We expect that the proposed folded corrugated SIW (FCSIW) slot antenna plays an important role for reducing the excessive backside radiation of the SIW slot antenna and for decreasing mutual coupling in SIW slot antenna arrays.

Mode Analysis of the Corrugated Substrate Integrated Waveguide

The corrugated substrate integrated waveguide (CSIW) is compatible with substrate integrated waveguides (SIWs) but permits ease of integration of active devices. The CSIW differs from the SIW by using quarter-wave open-circuit stubs in place of vias to form the electric sidewalls. In this paper, an efficient analysis method has been formulated that distributes the loading effect of each stub across its width. The formulation was used to calculate CSIW dispersion characteristics and identify mode behavior in the vicinity of the desired TE10 mode. Simulations and measurements of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> -band CSIWs were used to validate the calculations. Apart from normal waveguide mode behavior, surface wave-like behavior was also identified.