Surface Wave-Based Conformal Endfire Antenna With No Beam Tilt

This paper presents a surface wave-based conformal endfire antenna featuring a fixed beam direction with no tilt. The antenna is composed of two substrate layers: periodic Jerusalem cross structures on the lower layer and metallic strips on the upper layer, both conformally mounted onto a cylindrical metallic surface. A coaxial feed from the bottom excites an off-center-fed dipole (OCFD), which in turn activates surface waves on the periodic structures. To enhance the front-to-back ratio, four parasitic strips are strategically added aside of the OCFD - two serving as directors and two as reflectors. The use of thin substrates enables a compact, low- profile design. Full-wave simulations demonstrate the fixed beam direction to the endfire with no tilt over a bandwidth of 5.77-5.87 GHz. At the center frequency, the proposed endfire antenna achieves a gain of 9.8 dBi, while the integration of two antennas within a radome boosts the gain to 13.6 dBi.