Oscillator-type active-integrated antenna: the leaky-mode approach

The active leaky‐wave antenna arrays have been demonstrated, which integrate several microstrip leaky‐wave antenna elements with a single HEMT oscillator as an active source at 10.2 GHz. To excite the first higher order mode, the leaky‐wave antenna is fed asymmetrically. The reflected wave due to the open end of each leaky‐wave antenna element has been suppressed by the symmetric configuration of this antenna array. When comparing with the measured radiation pattern of the single‐element antenna, we found that 1×2 and 1×4 antenna arrays can effectively suppress the reflected power by more than 5.5 and 10.5 dB, respectively. Furthermore, the power gains are more than 2 and 3.16 dB higher than the single‐element antenna with a measured EIRP of 18.67 dBm. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 14–17, 1998.

Asymmetric feeding active leaky-wave antenna arrays

Wang

et al. 1998

Experiment on an aperture-coupled leaky-wave antenna with a pencil beam

Kao

et al. 1999

A frequency‐scanning leaky‐wave antenna with an aperture‐coupled feeding structure is presented. The aperture‐fed structure is used to excite the microstrip first higher mode. In order to suppress the dominant mode, we add a sequence of covered wire in the center of this antenna. The measured H‐plane main beam is a pencil beam, and is continuously scanned 12° as the frequency varies from 9.85 to 10.27 GHz. This feeding structure is very suitable for active phase antenna array applications. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 21: 5–8, 1999.

Scanning leaky-wave antenna integrated with self-oscillating doubler

Wang

Jou

1999

A new method which can enhance the scanning angle and elevate the operating frequency for active scanning leaky‐wave antennas is proposed in this paper. We know that the characteristics and performance of scanning leaky‐wave antennas are strongly dependent on the variation of the operating frequency within the leaky‐mode region. The self‐oscillating doubler without external oscillator sources provides double‐frequency variation at the second‐harmonic frequency instead of one‐frequency variation at the fundamental frequency. Therefore, the antenna scanning range can be enhanced and the operating frequency can be elevated. The measured scanning angle of this antenna is 13°, which agrees well with the predicted 13.7°, and the data show that the frequency‐scanning ability of the leaky‐wave antenna using a self‐oscillating doubler increases as predicted. This self‐oscillating doubler design is very simple, and it not only can improve the scanning capability of the active leaky‐wave antenna, but it is also very suitable for millimeter‐wave active antenna design. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 108–111, 1999.