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A Phase- and amplitude-adjustable metasurface radome (PAMR) is proposed to achieve a wideband high gain and low radar cross-section (RCS) antenna with arbitrary sidelobe levels (AS-PGMA) at a 9.8 GHz operating frequency. The proposed PAMR is a special multilayer phase gradient metasurface lens whose amplitude distribution is modified based on the Dolph-Tschebyscheff technique. The AS-PGMA simulation results indicate that a high gain, low RCS, and low sidelobe level (SLL) antenna can be achieved over a broad impedance frequency bandwidth of 9.25–10.1 GHz with in-band average values of 17 dB, −7.5dBsm, −20 dB/−27 dB for gain, RCS, and E-/H-plane SLL, which are measured at 9.8 GHz as 17.4 dB, −9dBsm, and −23.02 dB/−27.91 dB, respectively. Additionally, a novel analytical method for calculating the RCS of the proposed PAMR and AS-PGMA is described and verified by measurement and simulation findings. Measurement results show that the E-/H-plane SLL of the AS-PGMA is improved by 12.2 dB/5.1 dB at the operating frequency, respectively, while its gain and RCS reduction are reduced by 1.6 and 2.1 dB, respectively. Moreover, RCS of the AS-PGMA is reduced over an ultrawide bandwidth of 1–20 GHz for orthogonal polarizations. The analysis, simulations, and measurements are all in good agreement. [ABSTRACT FROM AUTHOR]

A novel theory based on the reciprocity theorem is presented for computing the plane wave scattered field of an arbitrary target, from its scattered field due to near-field illumination. The target is supposed to be illuminated by a transmitter probe on a cylindrical surface and the scattered near-field data is recorded in the near-field. The presented theory constructs a bridge between the scattered field due to the near-field illumination by a transmitter probe and that of plane wave illumination. Thus, referring to the definition of Radar Cross-Section (RCS) that assumes the incident field to be a plane wave, the RCS of the target can be analytically evaluated. For the verification of the proposed method, it is applied to an infinite conducting circular cylinder, which has an analytic solution for the infinite line source as a near-field source. Using the proposed theory the scattered field of such a target under plane wave incidence is evaluated, which is exactly identical to the same analytical scattered field under plane wave illumination. [ABSTRACT FROM AUTHOR]