Half-mode SIW based Active Integrated Circularly Polarized Leaky Wave Antenna for Automated Beam Scanning Applications

In this paper, an active integrated circularly polarized leaky wave antenna (AICPLWA) is proposed. The proposed design works in X-band. The leaky wave antenna is designed using half-mode substrate integrated waveguide technique, that provides circularly polarized beam. The proposed active integrated antenna consists of a leaky wave antenna section which is cascaded with active device to make a self-oscillating radiating structure. The leaky wave antenna has beam scanning ability by varying the input signal frequency and hence the oscillator section is modified using an active tunable reactance to provide a voltage tunable oscillation frequency to the leaky wave antenna section to achieve automatic beam scanning ability. The proposed active tunable reactance provides wider tuning range than commercial varactor for a small range of variation of tuning voltage. The proposed leaky wave antenna has a wide operating range covering the whole X-band and has axial ratio of better than −4.5 dB throughout the frequency range of interest. The oscillation frequency range provided by the active section is 10.5-10.95 GHz with the variation of tuning voltage from −4 V to −1.1 V. The AICPLWA covers an automated beam scanning range from 34°-40° for the 10.5-10.95 band. The proposed AICPLWA can be used in various applications such as microwave imaging, sensing radars requiring automotive beam scanning module.