This letter presents our design and experimental verification of a wideband dual-circular-polarized antenna operating in the W-band based on an optimized waveguide septum polarizer profiled smooth-wall horn. is capable transmitting receiving two orthogonal circular-polarized signals [left-hand circular polarization (LHCP) right-hand (RHCP)] simultaneously to achieve full-duplex, hence, twofold spectrum efficiency for millimeter-wave (mmWave) wireless communications. The fabricated shows 21%...

This paper presents our comprehensive study on a THz imaging system using linear sparse periodic array (SPA) at 220 GHz. A 8 Tx and Rx SPA is designed simulated, considering the issues of theoretical resolution, practical field view (FOV) ghost images suggesting guidelines designing such system. In order to verify proposed experimentally, we have investigated scheme that elements are located two scanning tracks separated by distance devised simplified experimental set-up only 1 channels. The...

This article presents a wideband dual-circular-polarization (dual-CP) antenna with high port isolation based on grooved-wall CP horn combined an orthomode transducer (OMT) in the W-band. A pair of grooves inner wall serves as inbuilt polarizer within antenna, which is capable generating both left-hand circular polarization (LHCP) and right-hand (RHCP) without any septum. The continuous linearly tapered groove design also allows this multisection to achieve low reflection coefficients over...

This article proposes an advanced THz multiple-input-multiple-output (MIMO) near-field sparse imaging scheme for target detection that uses single-pass synthetic aperture focusing and multipass interferometric techniques to improve effectiveness efficiency. It benefits from the MIMO of linear periodic array (SPA) random undersampling reduce sampling data system cost. Both simulated proof-of-concept experimental results have verified scheme, revealing approach is sufficient identify pure...

This article presents our study on a wideband miniaturized <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times8$ </tex-math></inline-formula> Butler matrix (BM) beamforming network based stacked metallic waveguide layout in millimeter-wave band. The size and complexity of the BM have been substantially reduced by introducing double-layer structure to avoid eight cross-overs using reverse feeding...

This paper presents our study on a single-offset parabolic reflector antenna operating at 220 GHz, which offers high gain as well the capability of beam steering for longdistance high-capacity terahertz wireless communications. With switch-controlled array placing offset focal plane primary feed, can be realized by selecting single element in different position to radiate using switches. The simulation shows that achieve up 55.19 dBi and 3dB scanning angle over ±3°.

This article studies the compressed sensing (CS) technique applied in THz linear sparse periodic array (SPA) imaging system, proposing corresponding image reconstruction model. The THz‐SPA system has been tested electromagnetic (EM) simulation, and then experimentally verified by using a simplified set‐up that only uses one transmitting channel receiving channel. reconstructed images based on both simulation experimental data have demonstrated feasibility of CS for reducing sampling but...

Relaying transmission is a candidate way to combat wireless channel fading and enlarge the coverage, efficient radio resource allocation essential provide quality-of-service (QoS) for networks. In this paper, an adaptive multiuser model proposed downlink of OFDM-relay system, which exploits performance gain in both frequency domain time domain. According different modes, two QoS-oriented scheduling algorithms based on feedback state information (CSI) hops are investigated. One enhanced...

This paper presents our study on a W band imaging system consisting of linear sparse periodic antenna array (SPA) with only 10 transmitting (Tx) and receiving (Rx) elements in simulation experiment for the purpose personnel screening. We have devised simplified low cost experimental set-up using 1 Tx Rx channels located two scanning tracks separated by distance to verify proposed multi-static scheme. The has taken account effects track separation measured patterns. correlate quite well,...

This study presents a novel design of circularly polarised horn antenna in W‐band with wide impedance bandwidth and 3 dB axial ratio (AR) bandwidth. By introducing pair grooves on the wall antenna, this simple compact structure is capable generating circular polarisation (CP) wave without any extra polariser expecting better power‐handling capability. The full‐wave simulation results show that 36.9% from 75.4 to 109.5 GHz can be achieved S 11 &lt;−21 AR&lt;3 dB, while directivity 16.56 ±...

A settling optimised sample-and-hold (SH) circuit with a wideband high-linearity input switch is presented. proposed floating-well isolation achieves low on-resistance and through wide frequency range. method for the SH to acquire behaviour by choosing feedback suitable achieve low-power target. Simulation results show that performance of improved considerably.

This paper presents our study on an Axially Displaced Ellipse (ADE) reflector antenna fed by a dual circular polarized antenna, which is able to provide both high-gain and Full-Duplex capabilities for mmWave wireless communication systems. The feed horn based stepped septum polarizer can generate Left Hand Circular Polarization (LHCP) Right (RHCP). An ADE also designed in order high gain while keep low reflection back the feed, when two orthogonal signals are transmitted received at same...

This paper presents a data-driven analysis of the relationship between students' English language proficiency and their academic performance in context transnational education. The research is conducted over comprehensive dataset composed module marks, subject-related results overall degree classification marks most recent four cohorts students who have graduated from UK-China Engineering programme. Spearman correlation hypothesis test was employed to analyse data identify patterns...

This paper presents a beam-steerable quadrifilar helix antenna (QHA) on an artificial magnetic conductor (AMC) surface for space based solar power application. The AMC is composed of 8 × square unit cells to suppress the current. By controlling input phases QHA ports through digital beamforming circuit, circularly polarized (CP) patterns can be steered within upper half space. To verify working mechanism, two passive polyphase feed networks are employed in measurement proposed at 5.8 GHz....

In this paper, a QoS differentiation adaptive retransmission limits ARQ (QDARL-ARQ) is proposed to improve the efficiency of in conventional SR-ARQ for IEEE 802.16e BWA systems. With simple algorithm implemented based on SR-ARQ, QDARL-ARQ scheme able dynamically adjust services with different characteristics by considering their requirements as well current system states simultaneously. This aims achieve lower packet error rate restrained end-to-end delay time-variable and prone wireless...

This paper presents our study on an offset parabolic reflector antenna with Polarization-Division Multiplexing capability operating at 300 GHz for terahertz communication systems that can achieve twofold data rate without increasing system bandwidth. The based the dual gridded structure is capable of in two orthogonal polarizations simultaneously a similar level high gain by using feeds.

This paper presents our study on the effect of perturbing variables and array size in optimizing a planar sparse based Danzer aperiodic tiling. A side lobe level below -12 dB has been achieved within wide bandwidth from f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> to 10 circular disk with radius 5λ , while -14.2 10λ . It is also demonstrated that covariance matrix adaptation evolution strategy (CMA-ES) outperformed other...

This paper presents our study on a planar wideband aperiodic sparse phased array and the effect of element mutual coupling. The in circular disk with diameter 10$\lambda$0 was optimized by using covariance matrix adaption evolutionary strategy (CMA-ES) together Danzer tiling to generate peak SLL(Side Lobe Level) factor less than -13dB without main beam steered -9.5dB 60 away from broadside band ranging f <inf xmlns:mml="http://www.w3.org/1998/Math/MathML"...

This paper proposes a THz linear sparse periodic array (SPA) personnel screening system using multi-pass interferometric synthetic aperture technique. The experimental results have demonstrated that the imaging can provide an improved image quality on resolution, signal to noise ratio and contrast than single-pass imaging.