Double-ring active microstrip antenna and self-mixing oscillator in C-band

Double-ring slot antenna with tree-shaped coupling strip for WLAN 2.4/5-GHz dual-band applications

“…In contrast to patch antennas, antennas with slot configurations exhibit improved characteristics, including wider bandwidth, less conductor loss, and better isolation [9]. Especially, the double-ring structure is a versatile approach for dual-band design [10,11], and a T-couple feed line based on the line-to-ring techniques for the circular disk is also available [12].…”

Active integration ring antenna/phase shifter with annular ring slot for 5-GHZ WLAN direct conversions

“…The direct-conversion receiver constructed with an antenna low-noise amplifier (LNA), a local oscillator (LO), a mixer, a phase shifter, and filters is shown in Figure 1. Therefore, it has the advantages of compact size, simple circuits, and low cost and it can be realized in an active integration antenna (AIA) [2][3][4][5][6][7][8].…”

T‐coupled circular microstrip antenna with H‐shaped aperture for bandwidth and radiation‐gain improvements

“…This design procedure is described and the simulated and experimental results, including frequency response and radiation patterns, are presented and discussed. This approach can be applied to received-only television (ROTV) systems, similarly to the double-ring microstrip antenna [14,15].…”