ULTRACAM is a portable, high-speed imaging photometer designed to study faint astronomical objects at high temporal resolutions. employs two dichroic beamsplitters and three frame-transfer CCD cameras provide three-colour optical frame rates of up 500 Hz. The instrument has been mounted on both the 4.2-m William Herschel Telescope La Palma 8.2-m Very Large in Chile, used white dwarfs, brown pulsars, black-hole/neutron-star X-ray binaries, gamma-ray bursts, cataclysmic variables, eclipsing...

An integration concept for multi-standard antennas is described. This technique based on utilizing a relatively large antenna that printed the top side of substrate, acting as ground smaller antenna. The onto bottom substrate. To validate this concept, an integrated wide-narrowband demonstrator presented. composed shorted microstrip patch with coplanar waveguide (CPW) fed ultrawideband (UWB) A prototype was fabricated and its performance verified. arrangement promising candidate applications...

This paper investigates the impact of intelligent reflecting surface (IRS) enabled wireless secure transmission. Specifically, an IRS is deployed to assist multiple-input multiple-output (MIMO) system enhance secrecy performance, and artificial noise (AN) employed introduce interference degrade reception eavesdropper. To improve we aim maximize achievable rate, subject transmit power constraint, by jointly designing precoding transmission, AN jamming, phase shift IRS. We first propose...

Ultrawideband (UWB) systems require band notch filters in order to prevent sensitive components, within the front-end of receiver, from being overloaded by strong signals. Recently, it has been shown that these can be integrated into UWB antenna, great advantage. This communication presents a new method for forming frequency response antenna. An open loop resonator is located on back substrate, used support monopole. The act separating antenna means they now designed isolation, using...

A two port frequency reconfigurable antenna for cognitive radios is presented. It composed of a disc monopole with ports that excite at opposite sides; one very wideband and consists coplanar feed line the other tunable narrowband microstrip defect slots in its ground plane. The act as filter suppresses frequencies outside desired band, operating band can be tuned by varying length slots. are decoupled least 10 dB through considered range. believed proposed good candidate generic small base...

In this communication, we introduce a glass dielectric resonator antenna (DRA) incorporating liquid-metal polarizer capable of polarization reconfiguration. The is formed by type alloy composed gallium, indium, and tin. generating three different polarizations: −45° (STATE 1), +45° 2), <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$y$ </tex-math></inline-formula> -axis 3). DRA designed to operate at 2.4...

This paper investigates a full duplex wireless-powered two way communication networks, where hybrid access points (HAPs) and number of amplify forward relays both operate in scenario. We use time switching (TS) static power splitting (SPS) schemes with networks as benchmark. Then, the new division duplexing (TDD SPS) (FDSPS) well simple relay selection strategy are proposed to improve system performance. For TS, SPS, FDSPS, best harvests energy using received RF signal from HAPs uses...

This article reviews the application and technology advancement of gallium (Ga)-based liquid metal (LM) in high-frequency circuits antennas. It discusses material properties common LMs, fluidic channels used to contain LM their manufacturing techniques, actuation which are all critical for design implementation LM-based devices. LM's pliable nature, together with its excellent electrical, thermal, rheological (i.e., fluid flow) properties, provides some unique innovative solutions...

This article presents the first substrate integrated waveguide (SIW) phase shifter that can be reconfigured using liquid metal (LM). digital exhibits low insertion loss and is reciprocal bidirectional. It incorporates a series of holes which filled or emptied metal, enabling us to add remove via connections dynamically, on-the-fly. Using collection such holes, it possible create wall along E-plane H-plane waveguide. When in place, blocks passage energy. absent, energy able flow. In this way,...

ABSTRACT In this letter, a novel frequency reconfigurable antenna with the aid of liquid metal is presented. The proposed incorporates 3D‐printed fluidic channel, which placed cross to metallized part radiator. Compared general meandered channels, channel ensures less be consumed, whilst it achieves same capability reconfiguration as solid patch. More importantly, allows have promised total efficiency thorough its switchable frequencies. can switch among 2.1, 2.6, 4.4, and 11 GHz, enabling...

This letter shows how slugs of liquid metal can be used to connect/disconnect large areas metalization and achieve a radiation performance not possible by using conventional switches. The proposed antenna switch its operating bandwidth between ultrawideband narrowband connecting/disconnecting the ground plane for feedline from that radiator. could achieved semiconductor However, such switches provide point-like contacts. Consequently, there are gaps in electrical contact Surface currents,...

The Total Energy Control System (TECS) is an integrated autopilot/autothrottle developed by BCAC that was test flown on NASA Langley's Transport Research Vehicle (i.e., a highly modified Boeing B737). This systems using principles of total energy in which the kinetic and potential airplane controlled throttles, distribution controled elevator. TECS integrates all control functions conventional pitch autopilot autothrottle into single generalized concept. integration provides decoupled...

A rigorous analysis is presented together with novel designs of high-gain sub-wavelength resonant cavity antennas. The antennas under investigation are formed by partially reflective surfaces placed in close proximity over artificial periodic metamaterial ground planes specific reflection phase responses. full-wave leaky-wave applied to this class for the first time and results reported discussed. Finite-size antenna studied at wireless LAN frequencies (3.7 GHz) using 3-D software compared...

This letter presents a passive UHF printed loop antenna with left-handed loading. The RFID reader can work at near- and far-field operation within the European (865-868 MHz) band. frequency radiation properties be modified by employing varactor diodes. Also, in near-field region having flat magnetic distribution interrogation zone. A comparative study other conventional antennas shows that achieves stronger near H-field good impedance matching. Design details, simulated results, fabricated...

A continuously steerable patch antenna employing liquid metal is presented. The proposed employs a novel tunable ground plane together with parasitic steering to steer the direction of main beam. consists permanent region, made from copper, and two regions formed metal. channels were fabricated using 3D printing technology. By injecting into channels, can provide continuous beam −30° +30° in elevation plane, while achieving low side lobe level performance combined scan loss performance. Such...

Antenna issues arising from the cognitive radio concept are introduced. There many possible ways in which systems could be configured. The range of antenna reconfiguration requirements is discussed, and some design approaches outlined. may involve bandwidth, pattern polarisation.

This letter presents a new approach for reconfiguring substrate integrated waveguide (SIW) devices. It involves allowing or prohibiting the wave propagation by using removable wall which is built from series of drill holes. When required, holes are filled with gallium-based liquid metal (LM), thus forming vias. no longer emptied LM. The method has been applied to single-pole single-throw (SPST) SIW switch as well double-throw (SPDT) switch. Both switches perform over wide frequency...

This article presents a proof of concept demonstrator for pair novel phase shifters based on substrate integrated waveguide (SIW) technology. Gallium-based liquid metal (LM) is used to reconfigure each shifter. LM that, the first time, have shifting range 360°. The small electrical size, and they are intended use within phased array antenna applications. also design procedure shifters. has been two operating at 10 GHz. process can be readily scaled operation other frequencies. proposed...

This paper presents a wideband circular antenna array with frequency-domain and space-domain reconfigurable radiation pattern. A is designed omnidirectional pattern, in azimuth direction, throughout the whole frequency band. The consists of eight TEM horn antennas. exhibits an azimuthal pattern when all ports are excited signals same magnitude phase. fed through bandstop filters power splitter. enables it to provide along single directional null given spatial direction at certain frequency....

Presented is an antenna that allows independent and versatile dual frequency bandwidth reconfiguration by using simple external matching circuits. Simulations suggest the has a total tuning range of 2118 MHz (from 778 to 2896 MHz) while maintaining return loss above 6 dB. In addition, capable operating as penta-band cellular phone antenna. This kind typically required work within GSM900, GPS1575, GSM1800, PCS1900 UMTS2100 bands.

This paper presents a new form of reconfigurable band notch resonator with wide tuning range. The whole structure consists through line and two parallel coupled resonators. an accurate lumped element equivalent circuit for the resonator. mechanism giving rise to range is also investigated. first harmonic fundamental stop-band analyzed compared that varactor-coupled Measurement results show filter can be tuned from 0.6 4.0 GHz. achieved by varying capacitance pairs varactor diodes. restricted...

Abstract This paper presents a design procedure for phased array feed network. The is validated by designing and fabricating set of 28 GHz 8‐element beam steerable antennas. Within the feed, Taylor n‐bar amplitude taper implemented using unequal power dividers. At boresight, reduced sidelobe level 2.84 dB to −15.2 dB. Beam steering from 0° 48° achieved meanders. An empirical formula meander widths proposed, enabling independent control phase. Empirical formulae initial parameters dividers...