A Switchable Integrated Structure of Broadband Wide-Angle Absorber and High-Efficiency Radiator

A switchable integrated absorber and radiator is proposed in this letter based on a planar ultra-wideband modular antenna (PUMA) structure integrated with PIN diodes. The switchable PUMA can serve as a resistor-free absorber by utilizing the semi-conductive mode of PIN diodes, or a radiator when the diodes are off. Additionally, a simplified-fed method for PUMA array is proposed, achieving excellent radiation performance comparable to a fully-fed array with per-element excitation. A 9 × 9 PUMA array prototype is fabricated and measured. For linear polarization, the measured 10 dB RCSR (radar cross-section reduction) bandwidths are 4–15.6 GHz (normal incidence), 4.3–14.8 GHz (TM 70°), and 5.8–16.6 GHz (TE 30°). For circular polarization, the 10 dB RCSR bandwidth are 4–15.6 GHz (normal incidence) and 5.5-14.9 GHz (CP 45°). Meanwhile, the prototype exhibits a measured -10 dB radiation bandwidth of 9.17-9.9 GHz and a peak gain of 14.9 dBi at 9.5 GHz. This work provides a new approach to designing integrated radiator and absorber structures, with potential applications in satellite or aircraft communications.