A Wideband High‐Efficiency Compact All‐Metal Folded Transmitarray With Integrated Planar Feed

ABSTRACT A wideband high‐efficiency compact all‐metal folded transmitarray antenna (CAMFTA) with integrated planar feed is proposed in this paper. It consists of a transmission metasurface (TMS) with the function of reflecting y ‐polarised wave, as well as transmitting x ‐polarised wave and twisting its polarisation by 90°, a linear polarisation conversion reflection metasurface (RMS), and a planar slotted patch as the feed. All these components are made of metal, making the entire structure relatively cheap to manufacture and resistant to stringent environments. Particularly, in addition to the low‐profile nature of the folded structure, the metal‐only planar feed is co‐designed and integrated with RMS, resulting in a further reduced profile and a compact configuration. In order to validate the superiority of the design, a CAMFTA is simulated, implemented and measured at X‐band. The results of experiments demonstrate a high degree of correlation with simulations, with peak aperture efficiency of 29% and 3 dB gain bandwidth of 13%, respectively. To the best of the authors' knowledge, this is the first CAMFTA reported in the literature, and it offers a number of advantages, making it very suitable for high‐gain applications where a compact, low‐cost, low‐profile configuration with steady performance is required.