We demonstrate a short (1.08 lambda(0)) microstrip leaky-wave antenna (MLWA) with suppressed back lobes and doubled frequency scanning region. The configuration of the proposed LWA contains three parts: the conventional open structure MLWA, the added monopole connected to the end of the MLWA on a defected ground plane, and the Yagi-Uda-like elements fabricated along the monopole. Because of the open structure of the MLWA, the reflected power produces a large back lobe radiated backwardly. By using the method of the added monopole connected to the end of the antenna, the remainder power could radiate through the added monopole without reflecting at the end. In addition, the Yagi-Uda-like elements fabricated along the added monopole enlarge the frequency scanning region due to the Yagi-Uda antenna characteristic. Compare to the conventional MLWA, the back lobe of the proposed LWA is suppressed about 8 dB at 5.0 GHz. The frequency scanning region of the H-plane (YZ-plane) of the proposed LWA can scan from 34 degrees to 57 degrees (total 23 degrees) while the frequency is operated from 4.6 GHz to 5.0 GHz; meanwhile the conventional MLWA scans from 30 degrees to 41 degrees (only 11 degrees) at the same frequency region.
- Added monopole; back lobe; frequency scanning; microstrip leaky-wave antenna (MLWA); Yagi-Uda-like elements