A High Gain and Fully Metallic Ku-Band Antenna Design based on High-Order Mode Method

This letter presents a fully metallic high-gain antenna operating in Ku-band. A high-order mode (HOM) method is employed to calculate the dispersion curves of periodic structure accurately. This approach enables convenient acquisition of the radiation efficiency of slot antennas, and provide a guidance for slot array design. A single-ridge waveguide is adopted as the transmission waveguide of the slot array, which effectively expands the operating bandwidth and narrows the array element spacing, thus greatly improving the aperture efficiency. Additionally, to accommodate the small spacing caused by the ridge waveguide, a compact H-plane ridge waveguide T-junction with a matching slab is designed for the feeding network. This T-junction requires no complex ridge deformation or additional impedance matching lines, thus effectively saving the space of feeding network. The measured peak gain of the antenna prototype reaches 33.45 dBi, with an operating bandwidth of 7.3%. Its radiation efficiency and aperture efficiency reach 85.2% and 81.4%, respectively.