Abstract Metasurfaces have provided unprecedented freedom for manipulating electromagnetic waves. In metasurface design, massive meta-atoms to be optimized produce the desired phase profiles, which is time-consuming and sometimes prohibitive. this paper, we propose a fast accurate inverse method of designing functional metasurfaces based on transfer learning, can generate patterns monolithically from input profiles specific functions. A learning network GoogLeNet-Inception-V3 predict phases...

A method of improving the diversity and capacity multiple-input-multiple-output (MIMO) systems in nonisotropic multipath environments by loading a scatterer array is proposed. The difference between super-resolution imaging discussed first. phase differences caused "effective space" adjacent antenna elements are critical factors enhancement. array, which made cross-structure periodically, placed on top to adjust center radiation pattern each port. By increasing "equivalent size" correlation...

In this article, a compact ultra-wideband balanced filtering power divider (FPD) with controllable cut-off frequencies is proposed based on the spoof surface plasmon polaritons (SSPPs). Firstly, SSPP unit cell designed using I-shaped microstrip structure for size miniaturization, and dispersion characteristics are analyzed. Next, highpass (PD) high common mode (CM) suppression level microstrip-to-slotline (MTS) transition feeding T-shaped slotline structure. A differential (DM) response CM...

A dual circularly polarized (CP) Fabry-Perot (FP) resonator antenna is presented in this paper. linear to circular polarization conversion metasurface (MS) employed as the superstrate of FP antenna. The working principle unit cell adopted by MS enables it independently control transmission and reflection characteristics. Firstly, designed present high reflectivity ensure gain Then capability endowed it. square patch can receive two orthogonal LP waves, cross slot on ground plane also make...

This letter presents an eighth-order dual-mode waveguide filter, fabricated using the selective laser melting (SLM) technique. The filter employs four dimpled ellipsoid resonators, operating at fundamental TM₁₀₁ mode. During printing, can be mechanically self-supported without any internal supports. Compared to filters employing tuning posts, proposed is less sensitive fabrication errors in terms of their impacts on passband return loss (RL), frequency shift, and bandwidth. was...

Conventional multiple vortex beams carrying different orbital-angular-momentum (OAM) modes propagating in directions suffer from beam divergences along with the increasing transmission distance, which greatly limits their practical applications. This article presents a diffraction-resisting dual high-order Bessel-beam (DHOBB) generator based on an anisotropic holographic impedance metasurface (AHIM) operating at 30 and 30.5 GHz. By virtue of leaky-wave theory optical principle, surface waves...

In this paper, an ultra-low profile anisotropic holographic metasurface is proposed to generate a linearly polarized high-order Bessel vortex beam carrying orbital angular momentum with predesigned topological charge. Based on the leaky-wave theory and optical principle, impedance pattern can be properly mapped by shaping quasi-periodic different meta-atom sizes. Compared prevalent spatial wave-modulated metasurface, surface effectively transforms reference wave excited feeding source in...

With the rapid development and explosive application of internet things (IoT) technology, IoT devices become ubiquitous indispensable in people's daily lives. with various forms massive production impose challenges on their over-the-air (OTA) testing. Nowadays, conducting OTA testing an efficient, reliable, cost-effective way has urgent demand for industry. Owing to particular properties (e.g., low cost, high efficiency, good repeatability) reverberation chamber (RC), it a popular facility....

In this letter, a 2-D Luneburg lens sandwiched by two parallel metallic plates is proposed. To support both the vertical and horizontal polarizations, plate waveguide (PPW) theory applied to analyze proposed lens. The results shown that height of consistence gains for each polarization has tradeoff relation. optimized approximate one operating wavelength. verify our idea, cylindrical fabricated using 3-D printing technique with radius 4.65λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

This article proposes a compact high-efficiency metallic resonator antenna operating at even-mode spoof surface plasmon polaritons (SSPPs). The collective electron oscillations within the structure increase effective relative permittivity that can be tuned by engineering dispersion of SSPP modes on structure. SSPPs are excited placing radiator their vicinity. As an example, is designed using comb-like proposed achieves low loss and hence high radiation efficiency because majority fields...

A frequency-diverse metasurface antenna with hybrid bunching methods for coincidence imaging is proposed in this paper. The contains an excitation system, a and double-layer-metal-plate system. Firstly, the system of divided into two parts, bunching-excitation module random-excitation module. includes seven-element coherent array that can generate beams 80 degree beamwidth from 32GHz to 36GHz; eight elements distributed evenly excite same working bandwidth. multilayer feed also designed...

The multi-mode orbital angular momentum (OAM) beams can be effectively applied in target detection when the divergence angles are equal. resolution threshold of coincidence imaging system with OAM is analyzed assisted by subspace projection method. First, relationship between and correlation function (CF) measurement mode obtained based on first-order algorithm for OAM-based (MM-OAMCI). Then, feature vector each unit extracted to distinguish point discretized plane. Finally, given three...

This paper proposes a broadband metamaterial aperture antenna (BMAA) with large capacity, low correlation coefficients and high radiation efficiency for coincidence imaging in the terahertz band. The BMAA consists of random modulated stripline structure as feed system. Firstly, element complementary electric-inductor-capacitor (cELC) is designed formed via randomly-distributed elements different resonant frequencies. By leveraging amplitude phase modulation characteristics elements, can...

In this paper, a novel design of circular polarized horn antenna is presented. An anisotropic metamaterial slab with metal periodic structures printed on substrate designed and its constitutive parameters S are analyzed. It shows that the can turn linearly wave to one. Then composed conventional rectangular fabricated measured. The results show radiates left handed an axis ratio below 3 dB at 16 GHz, gain radiation pattern same as those antenna.

This letter presents a 135–150 GHz high-efficiency and -power Schottky diode-based tripler integrated with low-loss waveguide filtering matching network. The active diode monolithic microwave circuit (MMIC) is matched two filters based on coupling matrix theory for two-port network complex impedance terminations. the MMIC are via microstrip-to-waveguide transition, allowing compact design relatively higher loss MMIC. In addition, an on-chip capacitor implemented to isolate dc RF paths....

To address the contradiction between extremely limited antenna space and numerous antennas within 5G mobile terminals, shared-aperture multiple have become a hotspot in recent years. Most only two elements. This letter proposes first three-antenna module using single floating metal without any additional decoupling measures, further improving usage efficiency. Two dipole modes are excited on coupled feeding approach, they decoupled by selecting proper port distance. The third antenna,...

A dual-band frequency selective surface (FSS) with different polarizations is proposed in this letter. The unit cell of the FSS composed three metallic layers and two intermediate dielectric layers. Each layer has a square loop circular patch twisted slot. When incident wave illuminates surface, transmission waves bands are different, i.e., one copolarization other cross polarization. performance been validated by both simulated measured results that good agreement.

In this paper, a novel frequency reconfigurable filtering antenna is proposed for modern wireless communication systems. The feed network composed of stepped impedance resonator filter and 50-Ω microstrip line. PIN diodes are used to switch the operate at either an ultra-wideband state or dual-band state. For state, operates both 3.35 5.2 GHz. measured results on tuning range, radiation patterns, realized gains provided, which show good agreement with numerical simulations.

This letter presents the design of a new type wideband waveguide matched loads. Unlike conventional loads based on absorbing materials, proposed relies conductor loss to achieve desired absorption level. To increase and meanwhile maintain small footprint whole device, gap structures are employed reduce group velocity wave inside waveguide. Additionally, is formed walls with low conductivity metal, yielding much higher loss. The load designed have spiral shape for further reduction size....

The orthogonal frequency division multiplexing (OFDM) based ground-penetrating radar (GPR) has been proven to have many advantages. estimation of amplitudes and time delays interface echoes is significant particularly in GPR systems for pavement profiling. For the recently developed OFDM-based systems, this letter proposes an algorithm precisely estimating echo delays. We estimate propagation channel domain transform resulted response domain. Considering reduction impulse (CIR) leakage...

In this article, a wide impedance bandwidth and gain Fabry–Perot resonator microstrip patch antenna based on metamaterials was presented. The metamaterial superstrate, which is constructed by doubly periodic array of complementary cross elements, achieved stable reflection phase response within the desired operation frequency range to broaden bandwidth. This worked at 13 GHz, simulated measured (S11 < −10 dB) 1.56 1.33 respectively. 3 dB about 1.1 results verified design. © 2016 Wiley...

The development of communication technology and the expansion spectrum have brought urgent demand for antenna miniaturization. In this letter, a method miniaturizing monopole antenna, which is based on deep-subwavelength property spoof surface plasmon polaritons (SSPPs), proposed. SSPP composed an structure interdigit capacitor near feeding impedance matching. height determined by engineering dispersion curves SSPPs. fed SMA connector whose ground connected to finite circular metal plate....

In the present paper, a new technique to reduce mutual coupling between linearly arranged patch antenna array is presented. Antennas are arrange in close space with edge-to-edge separation of 0.096λ and center-to-center spacing 0.29λ, where λ free wavelength. Two separate rectangular shape T-shape parasitic elements used cancel surface current (SC) order coupling. The placed antennas an extension towards boundary patches. obtained results indicate that for two consecutive less than -15 dB...