Compact and wideband cavity-backed antenna with elliptical coupling slot and elliptical aperture for satellite communications transceiver applications

A wideband full-metal cavity-backed antenna with elliptical coupling slot and elliptical aperture is proposed. The antenna consists of two elliptical structures, a coupling slot and a radiating aperture, which are placed on the feed waveguide side and the load side of a rectangular metal cavity resonator, respectively. By using an elliptical slot/aperture, the impedance bandwidth and gain of the antenna are found to be considerably improved in the same footprint and without increasing complexity compared to rectangular slot/aperture and also circular aperture. A prototype of the proposed wideband antenna is fabricated by using the additive manufacturing techniques of 3D printing with polylactic acid (PLA) material, which is covered with aluminum tape to validate the design at Ku-band for satellite communication (SatCom). The measured results show that the antenna has an impedance bandwidth of 4 GHz (10.86–14.86 GHz for |S11| < —15 dB), which gives a fractional bandwidth (FBW) of 31.1%. With low cross-polarization being less than — 25 dB at broadside, the antenna has a peak gain of 9 dBi. The proposed antenna is also compact, with a total volume of about 1.1λ0³ at the center frequency.