Substrate integrated waveguide leaky wave antenna with low cross polarization in X‐Ku band

Abstract

In this article, a balanced symmetrical low cross polarization (X‐pol) substrate integrated waveguide (SIW) based leaky wave antenna (LWA) is presented. The unit cell of the LWA consists of transverse and longitudinal slots, which provide series and shunt resonant elements, essentially required to radiate at broadside direction efficiently. The radiating slots are arranged in a way such that the unit cell is symmetrical around the centerline so as to achieve the low X‐pol levels. Moreover, the shape of the longitudinal slots are changed and optimized to match the unit cell impedance to the characteristic impedance of the SIW. Parametric constraints of the radiating slots are studied for achieving the continuous beam scanning and the best low X‐pol in the presented LWA. The final presented LWA is capable of continuous beam scanning from −28° to +30° within a frequency range of 9.5‐15.2 GHz including broadside at 12.2 GHz. Moreover, the X‐pol levels are better than −40 dB all over the scanning frequency range. Finally, the antenna prototype is fabricated and tested. Simulated and measured results are in good agreement. The maximum gain of the antenna measured is 13.8 dB.

Design of wideband end‐fire composite microstrip‐monopole antenna

“…It is obvious that microstrip Yagi antenna array 8,9 is a more suitable solution, since most of these designs 10,11 are limited by bandwidth. Leaky wave antenna is another form of endfire radiation 12‐15 . Similar to the electric or magnetic Yagi antenna, the endfire radiation feature is achieved by array characteristics, so a larger antenna size is inevitable.…”

A stable gain periodic microstrip leaky‐wave antenna with the open‐stopband eliminated

“…However, in recent years, most of the reported LWAs that can achieve continual backward-to-forward beam scanning are usually with significant gain variations. [16][17][18][19][20][21][22][23] In this article, a stable gain periodic microstrip LWA with the OSB eliminated is proposed. The periodic unit cell of the proposed P-LWA includes one transversal slot, two oblique slots, one parasitic patch, one narrow transversal slot and one metallic via.…”

“…Another method is to excite space harmonics with n = −1 in the periodic structure, so as to realize continual beam scanning from backward to forward. However, in recent years, most of the reported LWAs that can achieve continual backward‐to‐forward beam scanning are usually with significant gain variations 16‐23 …”

Compact bilayer substrate integrated waveguide leaky wave antenna with dumbbell‐shaped slot based on the TE 20 mode

“…On the other hand, in recent years, the substrate integrated waveguide (SIW) structures have been used widely in both articles and industry considering to ease of construction, low cost, planar structure, and their advantages over other transmission lines . Due to the advantages of this type of waveguide, using them in designing and manufacturing LWAs and power dividers has become very common in recent years …”

“…[8][9][10][11] Due to the advantages of this type of waveguide, using them in designing and manufacturing LWAs and power dividers has become very common in recent years. [12][13][14][15][16] Actually, the LWAs are two-port structures where the wave leaks outward through the structure, from the input port to the output port and forms the antenna radiation pattern. The scanning angle of the LWAs is depended on the β (the leaky-mode phase constant) and k 0 (free space wave number) and can be obtained from the Equation (1):…”