EMSIW-Based Compact High Gain Wide Full Space Scanning LWA With Improved Broadside Radiation Profile

A novel compact high gain eighth-mode substrate-integrated-waveguide (EMSIW)-based double asymmetry (DA) composite right-/left-handed (CRLH) leaky-wave antenna with larger degrees of freedom to control the efficiency is proposed and investigated. The proposed tilted DA radiating EMSIW incorporated with radiating interdigital capacitive (IDC) slots enables the unit cell to hold CRLH property with improved compactness and gain. The DA not only provides increased efficiency at broadside frequency than off-broadside but also offers more degrees of freedom to independently control the series and shunt resonators of the proposed geometry. Dispersion analysis is done by full-wave simulation and validated by theoretical analysis through predicted equivalent circuit model for achieving the balance condition of the unit cell which facilitates the complete elimination of open-stopband. Due to the systematic placement of interdigital slots on radiating EMSIW unit cell, the radiation intensity profile is significantly enhanced, which leads to higher directivity and notably enhanced gain (17.96 dBi). The proposed prototype is 5λ
₀
long having ten unit cells. The beam scanning range of the proposed antenna is 107° within 9-13.5 GHz, with the maximum broadside radiation efficiency of ~96%.