Radiation of High-Gain Cavity-Backed Slot Antennas Through a Two-Layer Superstrate

Abstract

The radiation of cavity-backed slot (CBS) antennas through a two-layer superstrate is studied in this paper. A novel transmission-line model is proposed to explain the gain-enhancement effect of the superstrate on cavity-backed slot antennas. Experimental result showed that a single cavity-backed slot antenna can achieve a high gain of 16.7 dBi through a properly designed superstrate, and this gain-enhancement property is valid for array configurations, as well. A rotationally arranged four-slot array, covered by the superstrate, is also investigated, to demonstrate that good circular polarization and high gain can be obtained from the superstrate-covered slot antennas.

Design of a High-Gain Cavity-Backed Slot Antenna With Mushroom Cells and Bent Ground Walls

“…To validate the results, the design presented in [21] is modeled with HFSS and the return loss and radiation patterns are presented in Figs. 2 and 3, respectively.…”

“…Cavity-backed slot antennas are extensively used in satellite communications and airborne phased arrays [12][13][14][15][16][17][18][19][20][21], because of their unique features: (i) they can provide unidirectional radiation, (ii) mutual coupling between elements is relatively low, which is desirable in the design of phased arrays; and (iii) they can be readily mounted flush to the surface of a flying object. It was noted that the gain of a superstrate-covered cavity-backed slot antenna as described in [16][17][18][19][20][21] was between 9.8 and 16.7 dB.…”

“…It was noted that the gain of a superstrate-covered cavity-backed slot antenna as described in [16][17][18][19][20][21] was between 9.8 and 16.7 dB.…”

“…The return loss and radiation patterns are also computed using a homemade FDTD program to verify the HFSS results and demonstrate the feasibility of the proposed configurations. Figure 1 shows the geometry of the initial antenna design, which is similar to the one in [21]. The antenna consists of a cavity of size L × W × d (length × width × height) fed by coaxial cable, connected to a slotted ground plane of size g × g. A s × s RT/Duriod superstrate of height t and ε r = 10.2 is placed at distance h from the ground plane.…”

“…1. The dimensions in mm of the initial presented in Table 1 are the same as those in [21]. This design is called "Original Design" in this paper.…”