A Lightweight, Wideband, Dual-Circular-Polarized Waveguide Cavity Array Designed With Direct Metal Laser Sintering Considerations

A lightweight, wideband, and dual-circular-polarized (CP) waveguide cavity array operating at Ku-band is proposed. To obtain dual-orthogonal linear polarizations (LPs), the basic radiating element is a square cavity fed by two waveguides. By properly tuning the feed networks, equal amplitude and phase of radiated electric field for two orthogonal polarizations can be obtained, culminating in a 16 x 16 dual-LP array. A wideband waveguide-based hybrid coupler is integrated with a dual-LP array to achieve the final dual-CP array. The proposed dual-CP array is fabricated by applying the direct metal laser sintering method. Its overall size is 288 mm x 288 mm x 52 mm, and it has weighted slightly less than 1.3 kg. The measured results show that for both the CP ports, the array has exhibited desirable bandwidth of 12.25-14.5 GHz (at VSWR < 2), and its isolation is better than 15 dB. The measured gain ranges from 29.5 to 32.4 dBic, while the axial ratio is better than 4.5 dB over the entire band. A total efficiency of over 60% can be obtained for both the LHCP and RHCP radiations.