The conventional Vivaldi antenna is known for its ultrawideband characteristic, but low directivity. In order to improve the directivity, a double-slot structure proposed design new antenna. two slots are excited in uniform amplitude and phase by using T-junction power divider. can generate plane-like waves E-plane of As result, directivity significantly improved comparison same size. measured results show that impedance bandwidth from 2.5 15 GHz. Gain considerably at frequencies above 6...

A new concept of planar magneto-electro-dielectric waveguided metamaterials (MED-WG-MTM) is proposed to manipulate the effective permeability μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> and permittivity ε . The MEDWG-MTM cell consists an electric complementary spiral ring resonator (CSR) in upper metallic plane a magnetic embedded Hilbert-line (EHL) ground plane. characterizations working mechanisms are investigated depth through...

In this paper, an efficient power allocation (PA) strategy is developed for maneuvering target tracking (MTT) in the collocated MIMO radar. The mechanism of our to implement optimal PA based on prior information cycle. predicted conditional Cramer-Rao lower bound (PC-CRLB) derived, normalized and adopted as optimization criterion, since PC-CRLB most recently realized measurement provides a more accurate than standard posterior CRLB (PCRLB). We fully demonstrate that established model convex....

A coplanar waveguide (CPW)-fed dual-band antenna operating at linear and circular polarization is presented in this letter. novel composite right/left-handed (CRLH) unit cell designed as a radiation element that can provide zeroth-mode resonance positive-mode the lower upper frequency. TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode orthogonal to +1st-Order excited by square complementary split-ring resonator (S-CSRR) order form...

A collocated multiple-input and multiple-output (MIMO) radar has the ability to track multiple targets under simultaneous multi-beam mode, where each transmit beam is defocused search entire surveillance space, then; a focused formed at receiver achieve higher resolution. joint power bandwidth allocation strategy developed in this mode. The optimization model established with aim of improving sum weighted posterior Cramer-Rao lower bounds (PCRLBs) targets, which predicted based on feedback...

How to utilize the limited antennas for tracking multiple targets plays a critical role in collocated multiple-input multiple-output radar. A dynamic antenna selection strategy is proposed address this problem. The basis of our achieve optimal under constraint active using feedback information recursion cycle, improving worst case estimate accuracy among targets. Since posterior Cramer-Rao lower bound quantifies target performance, it derived and utilized as optimization criterion. We then...

In this paper, we propose a novel direction of arrival estimation algorithm for multi-input multi-output radar in low-grazing angle (LGA) condition. Considering the effect earth curvature and atmosphere, derive received signal model based on assumption that waveforms are transmitted by widely spaced sensors some separated uniform linear arrays (ULAs). order to use multipath echo power, proposed can select best transmitter reflected coefficients optimizing virtual signal, remove coherency...

A low-profile, single-feed, single-layered dual-band patch antenna using mushroom-like transmission-line metamaterial (TL-MTM) structures is proposed in this letter. The characteristics of the new TL-MTM structure are initially studied detail by circuit analysis and HFSS simulation, working mechanism radiation performances examined illustrated for two operating bands, respectively. occupies an overall size 0.22λg×0.22 λg×0.042λg. Measured results exhibit that fabricated has a monopole-like...

A broadband electrically small antenna (ESA) based on simplified metamaterial transmission lines (SMTLs) is proposed in this letter. The consists of two different-sized SMTL unit cells different resonance frequencies. dispersion analysis the reveals that an increase series interdigital capacitance would decrease +1st-order mode frequency, thus reducing electrical size antenna. matching wideband enabled when frequencies suitably merge. fabricated prototype for WLAN/WiMAX applications has been...

A method to improve the performance of a wideband circularly polarized (CP) Fabry–Perot resonator antenna (FPRA) is presented in this communication. First, CP FPRA composed partially reflective surface (PRS) with positive reflection phase gradient and patch proposed. Then, transmission metasurface (MS) high magnitude tunable broadband range proposed correct electric field above antenna. This MS has ability independently tune phases two orthogonally waves. On one hand, nonuniform distribution...

This letter presents a novel type of compact, low insertion loss (IL) planar microstrip filter, which is mainly composed two hybrid resonators with mixed electric/magnetic (EM) coupling between them. Tunable EM constructed to realize tunable transmission zero (TZ) very close the passband. And folded T-shaped feed lines are adopted introduce another TZ and obtain desired external coupling. Advantages proposed filter not only its compact size IL, but also TZs.

Wideband decoupling requires simultaneous improvements in the performance of an antenna array its operating band. In this paper, a metasurface structure is proposed to accomplish difficult task wideband dual-layer coupled patch multiple-input-multiple-output (MIMO) arrays. The mechanism analyzed based on network and field theories, dual-band response achieved by incorporating multilayer hybrid split-ring resonators create meta-atom equipped with single negative property. By introducing into...

In this paper, on the basis of proposing a novel complementary split-ring resonator (CSRR) using Koch fractal curve, bandpass filter based such new structure is designed To validate designing method. Transmission characteristics and reflection presented are given by both software simulation experiment measurement. Consistent results have confirmed design concept excellent performance indicated that proposed has low insertion loss high selectivity small size.

A compact antenna using a novel linger-connected interdigital capacitor (FC-IDC)-based composite right/left-handed transmissionline (CRLH-TL) unit cell is presented. First, the characteristics of proposed CRLH-TL are investigated. Compared with conventional IDC-based cell, one has lower -1st-order resonant mode. Then, an designed, fabricated, and measured. By IDCbased microstrip patch, another two antennas also measured for comparison. The results show that based on FC-IDC achieves 21.98%...

An online pulse interleaving scheduling algorithm is proposed for a solution to the task problem in digital array radar (DAR). The full DAR structure explicitly considered way that waiting duration able be utilized transmit or receive subtasks, namely interleaving, as well receiving durations of different tasks are overlapped. decomposes analysis into time constraint check and energy check, schedules all kinds interleaved. Thereby both fully utilized. simulation results verify performance...

In this letter, a compact branch-line coupler using new type of uniplanar composite right/left-handed transmission line (CRLH-TL) is proposed. The obtained by etching spiral structure and series meandered capacitive gaps at both ends on the host line. With aid lumped element equivalent circuit model dispersion relations, CRLH property studied. By proposed structures, 90-degree phase shift 35.35 ohm 50 lines are designed for operating 1 GHz. Its occupied size only 32.5% that conventional one....

In this paper, a compact microstrip antenna with radiation pattern reconfigurable characteristic employing MEMS switches is proposed and investigated.This novel mainly includes four parts: circular-shaped patch, six switches, fan-shaped coupling cells cells.Through controlling the states of selectivity can be achieved.When switching operation from state 1 to 12 sequentially, main beam direction in azimuth planes could rotate 30˚ 0˚ 330˚ each switch.Meanwhile, directions elevation plane...

A compact branch-line coupler with an ultra-wide upper stopband is proposed based on a new type of transmission line. Consistent numerical and measurement results the are shown. The operating at 0.875 GHz exhibits from 2.8 to 12.9 suppression levels better than −20 dB. occupied size only 17.6% that conventional one same frequency.

A collocated multiple-input–multiple-output (MIMO) radar has the ability to track multiple targets in simultaneous multibeam working mode, where defocused beams are transmitted illuminate whole space, and focused received extract target information. fast power allocation (FPA) strategy is put forward this mode. The predicted posterior Cramer–Rao lower bound (PCRLB) cluttered background slighted relaxed utilized as optimization metric. model then established minimizing worst case of PCRLB...