Integrated Waveguide Cavity-backed Slot Antenna Research Articles

Bandwidth improvement of substrate integrated waveguide cavity-backed slot antenna with dielectric resonators

In the paper, a low profile substrate integrated waveguide based circular-shaped cavity-backed antenna is delineated to work at WLAN U-NII mid band and a slender rectangular slot is then placed at its center on the ground plane for radiation. The parent antenna radiates at 5.33 GHz with a gain of 4.9 dBi; depicting a narrow impedance bandwidth of 50 MHz. The antenna is modified by placing dielectric resonators of different shapes over the slot to enhance the bandwidth. The new antennas thus produced have an impedance bandwidth of 750 MHz with cylindrical-shaped and rectangular-shaped dielectric resonators which reflect bandwidth enhancement of 700 MHz for both the cases and an impedance bandwidth of 710 MHz with hemispherical-shaped dielectric resonator reflecting bandwidth enhancement of 660 MHz. The gain of the modified antennas is of the order of 4.7 dBi which basically indicates not much degradation in gain as compared to the parent antenna. All the antennas are delineated using Arlon AD270 substrate material with the results obtained after simulation juxtaposed with the ones obtained through measurement.

High Gain, Broadband and Dual-Polarized Substrate Integrated Waveguide Cavity-Backed Slot Antenna Array for 60 GHz Band

In this paper, a compact substrate-integrated waveguide (SIW) cavity-backed slot antenna array with high gain, broadband, and dual-polarization performances is proposed for 60-GHz applications. An enhanced 17.1% impedance bandwidth was achieved by cutting semi-circle edges on the conventional slot radiator. A simplified SIW feed network is aperture-coupled vertically and constructed on a double-layered structure to implement the dual-polarization operation. By adopting innovative techniques on both radiating element and double-layered SIW feed networks, a high-gain, broadband, and dual-polarized $8\times8$ antenna array was designed on three-layered printed circuit board that allows for mass production. This configuration also resolves the trade-off between the bandwidth and gain of the existing 60-GHz dual-polarized antenna array. Its feasibility is proved by obtaining a measured gain in the range of 19.7–22.3 dB and an enhanced impedance bandwidth of 17.1% over 55.7–66.1 GHz for both horizontal and vertical polarizations. With advantages of high-gain, broadband, and dual-polarization performances in a low-cost low-profile structure, the proposed antenna array is a promising candidate for millimeter-wave wireless systems.

Design of Self-Diplexing Substrate Integrated Waveguide Cavity-Backed Slot Antenna

In this letter, a novel design technique to realize planar self-diplexing slot antenna using substrate integrated waveguide (SIW) technology is presented. The proposed antenna uses a bowtie-shaped slot backed by SIW cavity, which is excited by two separate feedlines to resonate at two different frequencies in X -band (8–12 GHz). By properly optimizing the antenna dimensions, a high isolation of better than 25 dB between two input ports is achieved, which helps to introduce self-diplexing phenomenon in the proposed design. The behavior of the individual cavity modes at two resonant frequencies is explained using half-mode theory. The proposed antenna resonates at 9 and 11.2 GHz with unidirectional radiation pattern and a high gain of 4.3 and 4.2 dBi, respectively.

Gain-Enhanced SIW Cavity-Backed Slot Antenna with Arbitrary Levels of Inclined Polarization

This letter describes a gain enhancement method for a dual-polarized substrate integrated waveguide cavity-backed slot antenna by using a high-order cavity resonance to generate arbitrary levels of inclined linear polarization (LP). To do so, the metal posts are embedded in a main cavity to excite the ${\rm TM}_{220}$ mode of the cavity and control the amount of coupling to generate adjustable inclined linear polarization. To validate the simulated results, an antenna is designed, manufactured, and tested. The proposed antenna exhibits high front-to-back ratio (F/B) of more than 20 dB in the broadside direction and a relative gain of 6.9 dBi at the resonant frequency. The antenna can also provide an adjustable inclined LP with an aspect ratio of $E{x_{\max}}/E{y_{\max}}$ ranging from 0.23 to 4. The proposed method can also be utilized to achieve even higher gain by exciting higher order mode cavity resonances, such as ${\rm TM}_{440}$ and ${\rm TM}_{660}$ . The proposed antenna exhibits the advantages of simple feed network and more compactness compared with the SIW cavity-backed slot antenna/array that has the same gain with inclined polarization.

Broadband Substrate Integrated Waveguide Cavity-Backed Bow-Tie Slot Antenna

A novel design technique for broadband substrate integrated waveguide cavity-backed slot antenna is demonstrated in this letter. Instead of using a conventional narrow rectangular slot, a bow-tie-shaped slot is implemented to get broader bandwidth performance. The modification of the slot shape helps to induce strong loading effect in the cavity and generates two closely spaced hybrid modes that help to get a broadband response. The slot antenna incorporates thin cavity backing (height <;0.03λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ) in a single substrate and thus retains low-profile planar configuration while showing unidirectional radiation characteristics with moderate gain. A fabricated prototype is also presented that shows a bandwidth of 1.03 GHz (9.4%), a gain of 3.7 dBi over the bandwidth, 15 dB front-to-back ratio, and cross-polarization level below -18 dB.