Substrate Integrated Waveguide Based One Dimensional Leaky-Wave Antenna with Enhanced Scanning Range and Consistent Gain Characteristics

Abstract

In this paper, a new approach of designing single layer Substrate Integrated waveguide (SIW) based planar leakywave antenna for X-band (8-12 GHz) application is presented. The beam scanning range of the final prototype is found to be $85^{\circ}(-60^{\circ}$ to $25^{\circ})$. This design consists of a new type of unit cell, which is the combination of three transverse and three longitudinal rectangular slots. These slots are arranged periodically. The peliodic loading of these slots incorporates capacitive coupling, which is further responsible for a wide range of scanning. The designed antenna is showing a high impedance leakv-wave region. The most challenging task for a leaky-wave antenna is continuous beam scanning from the backward-to-forward with a broadside radiation patterns. In this paper, the designed LWA achieves this task with a significant reduction in side lobe level (SLL) and cross-polarization. The final prototype with directive beam and stable gain characteristic in the desired frequency band is designed. It is found from the radiation pattern that SLL for all the frequency is below -15 dB and cross polarization level of $-\mathbf{1 8}$ dB. A thorough analysis of dispersion diagram of the unit cell and radiation characteristics using fundamental TE10 mode of SIW is conducted using a full-wave EM-simulator.