Search

In this article, the oversized substrate-integrated waveguide (OS-SIW) is proposed, analyzed, and experimentally demonstrated. The physical parameters and the effect of material surface roughness on the attenuation and the SIW power capability lead to the exploitation of wider and thicker waveguides, as an alternative to enhance the power-handling capability (PHC) and reduce the losses. The resulting oversized waveguide is a guide whose width or thickness is greater than that of the SIW, which is sized to support only the TE10 mode in the operating band. An SIW-to-OS-SIW transition has been designed to allow the component characterization in the W-band. The proposed transition allows to propagate only the desired mode TE10 in the OS-SIW and prevent the higher mode propagation. The experimental results of the manufactured prototypes accord well with the simulations in terms of power handling and transmission losses. The proposed OS-SIW line shows lower attenuation (1.5 Np/m) than a standard SIW (3 Np/m) or a microstrip line (about 3.7 Np/m). However, the OS-SIW 5a has achieved an average power of 90 W at 90 GHz. The investigated OS-SIW configuration offers high PHC, low losses, and easy integration into high-power millimeter-wave systems. [ABSTRACT FROM AUTHOR]

Abstract: A planar waveguide and a rounded bend is proposed, designed, and implemented through a hybrid structure of substrate integrated waveguide (SIW) and electromagnetic bandgap (EBG) material. In order to design the EBG waveguide, a square lattice of air holes situated between two metal plates is used. The SIW line and bend are inserted on EBG waveguide to enhance performance. These devices were fabricated and measured. The experimental results show a homogeneous agreement with the simulation. The combination EBG‐SIW covers almost the whole EBG bandwidth of 6 GHz (17%) around 35 GHz. The proposed hybrid integration technique presents a competitive candidate for the development of millimeter‐wave circuits and systems. [ABSTRACT FROM AUTHOR]

The microstrip patch antenna (MPA) with frequency stability versus temperature is proposed as the ice sensor for de-icing of aerodynamic systems. The operation principle is based on the fact that the formation of ice layer is set to disturb the near fields, thus shifting the resonant frequency. To mitigate the uncertain temperature effect, a thermal stability (TS) strategy is implemented, making the sensor only susceptible to the ice loading effect and enabling stable performance within a large temperature range from − 40∘C to + 80∘C. The proposed ice sensor is in turn interrogated wirelessly by a transmitting (Tx) antenna. Due to the frequency shift, the received signal strength (RSS) is modulated as a function of ice-thickness, allowing for remote ice detection and quantification. Two common types of ices, namely rime and clear ices, are investigated. The ice samples were generated and characterized under different weather conditions in our cold chamber and wind tunnel at Anti-icing Materials International Laboratory (AMIL) with the University of Quebec at Chicoutimi (UQAC). Experimental results show the feasibility of the proposed approach for different real-world scenarios. In particular, the sensor demonstrates the best measurement capability in the case of clear ice with full coverage, achieving the sensitivity of 75 mV/mm. [Display omitted] [ABSTRACT FROM AUTHOR]

A class of directional couplers based on the substrate integrated waveguide (SIW) technique for compact three-dimensional (3-D) integrated circuits is proposed and studied in this work. Backward and forward couplers as well as strong coupling-defined forward couplers are presented and developed. They are composed of two joined SIW sections such that the common wall between them is made of a portion of the broad side of the first SIW and the narrow side of the second SIW. This perpendicular topology is arranged and formed through the use of a LEGO-like interconnect between the two SIW structures. Different coupling geometries developed with a low-cost printed circuit board process are studied. Design considerations and measured results at Ka-band are presented and discussed. To achieve respectively weak backward and forward directional couplings, Schwinger and multihole-type directional couplers are introduced first of all, which make use of coupling slots arranged around the center of the SIW broad wall. For each of those structures, a wideband 20-dB directional coupler is fabricated and measured for demonstration purposes. To achieve a strong coupling, a Riblet-type directional coupler is proposed and examined. Subsequently, a 3-dB coupler is demonstrated together with a 0-dB coupler, offering a wideband and very efficient transition between the perpendicularly arranged SIWs. The proposed directional couplers can be used at millimeter-wave frequencies for probing and the design of compact 3-D integrated circuits and systems such as polarimetric imaging radiometer or antenna array feeding networks. [ABSTRACT FROM PUBLISHER]

This study presents a compact circularly polarised array using tapered slot antenna fed by a substrate integrated waveguide (SIW) power divider. With the proposed topology, broadband circularly polarised property is achieved and total gain can be increased by controlling the element length, conserving the same footprint area. The different 2 × 2 cell configurations are investigated. Simple and integrated series-parallel SIW feed for the choose cell is presented. A 2 × 2 antenna array is designed and fabricated using SIW E-plane power divider. The measured 10 dB return loss and 3 dB axial ratio bandwidths are 35.65 and 32.3%, respectively. The measured antenna gain is 14.4 dBi at 35 GHz. [ABSTRACT FROM AUTHOR]

This paper proposes and presents a class of substrate integrated waveguide (SIW) power dividers/combiners based on a modified Wilkinson architecture. The proposed design consists of a ring-type circuit of \(1.5~\lambda _{g}\) length with three waveguide ports. Impedance variation without affecting cutoff frequency and integration of isolation resistance are the two major limitations in connection with the design of SIW Wilkinson structures. Central ring part with different thickness ensures different impedance in the first proposed scheme while the half-mode SIW in the second option. As for the second limitation, the optimal configuration of integrating the isolation resistance is studied. A version without resistance is also examined using a broad-wall series slot. To validate the proposed concept, a bilayered circuit with standard Printed circuit board prototype was fabricated and measured. A table summarizing performances of all the proposed circuits shows a bandwidth of around 25% at the 10 dB reference. A negligible additional insertion loss is observed. The proposed design techniques are found useful at millimeter-wave frequencies where reduced physical dimensions make a circuit configuration suitable for low-cost implementation. This concept is also valid for rectangular waveguide counterparts. [ABSTRACT FROM AUTHOR]

A Butler matrix-fed two-dimensional (2-D) scan linearly polarized 2 \times 2 microstrip ring antenna array (MRAA) is proposed and validated in low-cost substrate integrated waveguide (SIW) technology for Ka-band applications. The highly efficient, compact, and passive beam forming network (BFN) consists of SIW cruciform couplers as coupling unit, and its special topology is well adapted for feeding planar arrays. The wideband and high radiation efficiency antenna elements are aperture-coupled through slots etched on the top of a high permittivity SIW feed substrate. Such four antenna elements are used to construct 2 ~\times 2 MRAA and to form four fixed beams, one in each quadrant at an elevation angle of 20^\circ from the broad side array axis. A triangular grid arrangement is chosen to avoid grating lobes in the visible space. A 50-\Omega grounded coplanar waveguide (GCPW) to SIW transition is used to avoid spurious input feed radiation loss. The array is measured to exhibit 3-dB beam width of 30^\circ in both of the orthogonal planes, radiation efficiency of 70% for each port, and stable radiation pattern bandwidth of 7.6% at 26.5 GHz. The physical size of the demonstrated 2 \times 2 array is 2.86\lambdao\times 2.86\lambdao\times 0.22\lambdao. [ABSTRACT FROM PUBLISHER]

A new temperature compensation method is proposed and demonstrated in this paper for cavities and filters realized in substrate integrated waveguide (SIW). The SIW structures largely preserve the well-known advantages of conventional rectangular waveguide, namely, high Q and high power capacity, and have the advantages of microstrip lines, such as low profile, small volume, and light weight. In this paper, we demonstrate that by an adequate selection of substrate properties, SIW cavities can provide self-temperature drift compensation. The compensation is achieved by using an appropriate ratio between the coefficient of thermal expansion and the thermal coefficient of the permittivity. The theoretical prediction is confirmed by an experimental investigation using inductive post filters. Three commercially available substrates are used to design cavities at 10 GHz with the Roger TMM10 substrate providing a close fit to the required characteristics for temperature compensation. The results for the cavity show a stability of 2 ppm/^\circC in calculation and 8 ppm/^\circC in measurement. A SIW fourth-order Chebyshev filter, centered at 10 GHz with 1-GHz bandwidth, has also been designed. The measured frequency drift is 9.1 ppm/^\circC and the bandwidth variation is \pm \0.13\\% over the temperature range of -\40\ ^\circC to +\80\ ^\circC. [ABSTRACT FROM AUTHOR]

In this article, a multilayered substrate integrated waveguide (SIW) Butler matrix beam-forming network is proposed, designed, and demonstrated at 24 GHz for automotive radar system applications. The proposed low-cost SIW structure can be used to develop a highly integrated multibeam antenna platform in automotive radar systems and other applications. In this structure, an SIW H-plane coupler is optimized with an H-plane slit to provide the required phase shift. A class of SIW E-plane 3-dB couplers in doubled layer substrate are studied and designed as the fundamental building blocks to avoid crossovers usually required in the construction of a Butler matrix. A 4 × 4 matrix is investigated and designed, which shows excellent performance over 22-26 GHz frequency band. Two types of antenna are tested with the proposed matrix scheme. First, an antipodal linearly tapered slot antenna (ALTSA) is incorporated into the Butler matrix to verify the broadband performances. Second, a longitudinal slotted waveguide antenna array is examined to generate radiation patterns in the broadside direction. Measured results agree well with simulated counterparts, thus validating the proposed multilayer SIW design concepts. In the next sections, the use as feeding networks for providing the reconfigurability operation of an antenna will be illustrated. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2012. [ABSTRACT FROM AUTHOR]