Coaxial Periodic Leaky Wave Antenna with Narrow Beamwidth and Improved Broadside Gain

This paper presents a periodic leaky wave antenna (LWA) using a coaxial cable. Leaky mode radiation is obtained from periodic slots etched on the outer conductor of the cable. Further, a periodic impedance matching unit is used to improve radiation through broadside. The main beam scans from -19 degrees in the backward direction to +13 degrees in the forward direction through broadside when the operating frequency is changed from 8 GHz to 11.5 GHz. The impedance matching unit helps to improve the broadside gain by 9.3 dB. The measured broadside beam width is 6 degrees at 9.9 GHz, with a gain of 10.26 dBi. Lateral dimension of the antenna is just 6.3 mm and can be easily integrated in a microwave system.