High-Gain Single-Feed Overmoded Cavity Antenna with Closely Spaced Phased Patch Surface

High-gain single-feed antennas are desired for current and future wireless systems. Slot-based highly overmoded cavity antennas are one solution, but the fact that they can only radiate broadside beams limits their applications. An innovative phase-control technique is developed for slot-based resonant cavity antennas that utilize a planar array of closely spaced, appropriately sized metallic patches integrated into the very near field of their slot arrays. It facilitates the design and realization of the phase distribution over their radiating aperture that is required for them to generate single and/or multiple tilted beams pointed at specified directions. A TE(10)(11)(0)-mode slot-based cavity antenna is selected as the pathfinder system. A TE110-mode single-slot cavity antenna that is equivalent to the half-wavelength subsection of that cavity is introduced initially to monitor the phase radiated from each slot. The phase control surface is then carefully engineered to facilitate tilted output beams from the base design. The approach is validated with two subsequent tilted-beam systems. The first system achieves a single beam tilted to 30° with respect to the broadside direction. The second system is extended to produce two independently directed titled beams pointing at-10° and 20°, respectively. All of the measured results agree well with their simulated values.