Slotted Waveguide Antenna with High Gain Omnidirectional Radiation Pattern in E-Plane

In this paper, a series of waveguide-based antennas with slots on both broad walls are proposed to achieve omnidirectional radiation. The unit cell of the proposed antenna is thoroughly investigated aiming to obtaining optimal omnidirectional pattern in E-plane. It is pointed out that the width of broad wall of the host waveguide is a key geometry parameter affecting the roundness of the E-plane pattern. The unit cells can be cascaded to form a series-fed array which is available for both standing wave and travelling wave excitation. All the slots on the same wall of the host waveguide are aligned collinearly by deploying meandering waveguide cavity instead for optimal synthesized E plane pattern. Several antenna prototypes are simulated for S-band application with gain variation in E-plane pattern smaller than 1 dB.