This article proposes a new method to realize low-profile broadband absorber. The unit cell of the proposed absorber consists two layers: lossy layer with four rotationally symmetric bent metallic strips embedded chipresistors, which is modified from doubly fed dipole antenna, and ground separated by an air spacer. Three resonant modes strip chip-resistors are generated, current in passes through under different it finally consumed, resulting energy dissipation. As result, ultrawideband...

This article proposes a hybrid absorptive–diffusive frequency-selective radome (AD-FSR) that has broadband transmission window with wide absorption and diffusion bands located at two sidebands, respectively. The proposed AD-FSR consists of resistive sheet bandpass surface (FSS) integrated coding metasurface separated by certain distance. band is realized the combined effect FSS as reflector in its lower stopband, while broad passband obtained when electromagnetic (EM) wave penetrates through...

A novel theory is proposed in this article to design a bandpass frequency-selective surface (FSS) with stable angular response. Based on theory, the performance of structure closely related its tangential and normal components permittivity permeability. Theoretical formulas are derived realize high-efficiency transmission response independence. To validate our concept, an ultrawide-angle FSS metallic strips square patch printed dielectric substrate designed, it exhibits characteristic...

In this article, a novel method for developing dual-polarized broadband microwave absorber (MA) use at an extremely oblique incidence angle is presented. A detailed theoretical analysis performed and formulas are derived to obtain the required relative permittivity permeability tensors achieve absorption arbitrary angle. As proof of concept, MA operating <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math...

A new methodology for designing a dual-polarized absorptive frequency-selective reflector (AFSR) with wide reflection and absorption bands is proposed in this communication. The AFSR made up by an array of interweaved bent metallic strips embedded chip-resistors the center on ground. absorption- reflection-absorption response obtained generating multimode resonance wave antinode wave-node characteristics structure. Four are together to realize performance its rotational symmetry...

A cognitive antenna array, which is designed by using deep reinforcement learning (DRL) proposed in this article to adapt the complex electromagnetic environment. Specifically, phased array utilized as manipulatable component achieve characteristic of beam steering with help DRL algorithm. We begin establishing a DRL-based framework, comprised microprogrammed control unit, power divider, digital phase shifter, and patch array. In algorithm, desired obtained through trial-and-error...

This article introduces an amplitude and phase independently adjustable transmitarray aperture with a thin profile low cost to fabrication characteristics, antenna (TA) featuring the high gain sidelobe level (SLL) is realized based on it. The TA made up of standard feed horn aperture, each which comprises three-layer metasurface that well-designed tune transmitted its own. As result, can cover 360° range required for compensation while also realizing distribution calculated by Taylor design,...

Abstract The Brewster effect plays a significant role in the transmission of electromagnetic waves with transverse magnetic mode or p‐polarization at specific angle. Here, electric ultrawide‐angle ultralow‐reflection phenomenon is proposed to realize perfect transparency ultrawide incidence angles. Theoretical formulae are derived provide basis for and explain characteristics achieving an response. As proof concept, metasurface response designed measured, whose relative permittivity...

A structure for the design of dual-band dual-polarized quasi-elliptic frequency selective surfaces (FSSs) is proposed in this letter, whose unit cell composed multiple arrays cylindrical dielectric resonators with capped annular ring inserted a perforated metallic plate. The designed FSS provides filtering responses two transmission poles (TPs) passbands and zeros (TZs) upper stopbands. So does it an incident wave either TE- or TM-polarization each band. In addition, including center...

Intelligent reflecting surface (IRS) is a promising new paradigm to achieve high spectral and energy efficiency for future wireless networks by reconfiguring the signal propagation via passive reflection. To reap potential gains of IRS, channel state information (CSI) essential, whereas estimation errors are inevitable in practice due limited training resources. In this paper, order optimize performance IRS-aided multiuser systems with imperfect CSI, we propose jointly design active transmit...

The array antenna will be inevitably deformed affected by the motion of communication system or other special requirements, which reduce original good radiation performance, such as gain dropping, sidelobe increasing, and even beam splitting. To cope with deterioration caused antenna’s deformation, it is necessary to quickly manipulate amplitude phase distribution according current conformal shape stabilize beam. This article proposes a physical-method-driven deep-learning-based (PMDL-based)...

This letter introduces a transmission frequency selective surface (FSS) with excellent roll-off feature, ultrathin thickness, low insertion loss, and wide rejection bands. Three novel basic component structures are developed based on the polarization rotator structure leading to multitransmission zeros poles that can be independently controlled. Theoretical analyses simulations carried out, prototype is fabricated measured. The proposed FSS exhibits double sharp sidebands, thickness as well...

The design of wide-passband dual-polarized elliptic frequency selective structures (FSSs) is proposed in this paper. unit cell the structure comprised an array cascaded square-patch resonators with a coupling layer consisting two types modified C-type and all-through slots. designed FSS provides third-order filtering response, three transmission poles passband zeros at below above passband, respectively. fabricated its performance measured. measured results confirm that achieves desired...

This article investigates the pattern synthesis of conformal phased array antenna (PAA) by using deep deterministic policy gradient (DDPG) algorithm, and a nearly full solid angle for beam steering is realized. The capability planar PAAs theoretically compared at first, conclusion obtained that conformed to conical-and-cylindrical structure can help achieve ultrawide-angle steering. Next, typical reinforcement learning which DDPG utilized deal with fast problem heterogeneous PAA. By virtue...

In this article, an integrated low-profile low radar cross section (RCS) circularly polarized (CP) antenna array based on multifunctional modes generation method is proposed, which can realize good in-band radiation performance and wide out-of-band RCS reduction characteristics the same layer without additional subassembly except for resistors. By embedding a resistor in center of metallic strip, half one half-wavelength resonant are changed into absorption modes, while wavelength mode...

Conformal array antennas (CAAs) can effectively broaden the beam scanning range and improve radiation flexibility. Unfortunately, confirmation will increase difficulty of analysis synthesis, stealth CAAs is arduous. In this article, we propose an innovative optimization algorithm for stealthy based on twin delayed deep deterministic policy gradient (TD3) algorithm, which combines advantages learning reinforcement learning. Furthermore, characterize CAA as electromagnetic model (EMM) embed it...

A method for designing a wideband low radar cross section (RCS) antenna is proposed based on hybrid absorptive and diffusive frequency selective reflector (AD-FSR) in this paper. The RCS exhibits manifold responses three artificial bands, which are created by its different components. simple U-slot patch borrowed, integrated with the diffusion metasurface, placed under sheet about quarter wavelength. Then, out-of-band incident wave captured absorber lower band, diffused metasurface upper...

A diffusive–reflective metasurface with dual independent bands is designed in this letter, which can be utilized to achieve specular reflection the middle band and radar cross-section (RCS) reduction sidebands. The made up of two elements, one consists diagonally arranged arrows tails different lengths, another its mirror structure. Two are realized based on resonances different-length tails, their current distributions parameter analysis given for comprehensible theory. Then, a prototype...

This paper introduces an angular-insensitive dual-polarized 3-D absorptive frequency-selective transmission structure (AFST), which has a window and upper absorption band. The band is produced by lossless resonators implemented using aperture antenna embedded notched parallel plate waveguide with metalized via hole in the center. obtained lossy constructed single resistor bent metallic strips. In addition, whole without backing discontinuous ground plane, overcomes fabrication difficulty of...

A modified triangle quarter-wavelength patch is proposed in this letter, and a compact circularly polarized (CP) antenna designed by combining two of them. The evolution process the combined patches depicted, current distribution analyzed to illustrate right-hand radiation generated antenna. In order achieve better performance, subarray with high-gain characteristics consisting four radiators power network fabricated within size 0.176 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

This article proposes a new multipolarization antenna, and its multiple states of polarization are realized by scanning the operating frequency. The proposed antenna is based on fixed configuration fed single port. extremely simple attractive in many applications, such as frequency-agile radar systems target identification systems, especially for those at higher microwave millimeter-wave frequencies. combining bidirectional planar with carefully designed rotating reflector. reflector...

This article describes a dual-band diffusive metasurface-based reflector, with specular reflection band together two sidebands which exhibit low radar cross-section (RCS). A rhombus-shaped patch-ring type of polarizer characteristics is chosen as the fundamental unit cell. The and its mirror structure have opposite phases in polarization-rotating bands, while their phase same band, juxtaposed in-between middle bands. designed metasurface constructed, based on cancellation theory, by...