PACER (Phased Array Concepts Evaluation Rig) is an experimental, receive only, phased array that has been designed and built at DERA Malvern. The array operates at X band and has been constructed as a facility to support DERA research associated with the tri-national AMSAR airborne phased array demonstrator programme, and other future generation phased array radar systems. PACER is a unique facility, and the flexibility of the design offers considerable scope for practical research into adaptive array signal processing and future research associated with advanced phased array concepts (wideband operation, RCS reduction, bistatic operation, element level digitisation approaches). To date, the array has been used primarily as a source of real phased array data for validation of adaptive beamforming techniques. This paper includes some detail of the design and build of PACER in addition to the results of adaptive array signal processing experiments to demonstrate jamming rejection and estimation of the directions of closely spaced sources View full abstract»

We have used silicon technologies to build highly dense phased array for X to W-band applications. Typical designs include an 8-element 8-16 GHz SiGe phased array receiver, a 16-element 30-50 GHz SiGe transmit phased array, a miniature (<; 3mm²) and low power (<;100 mW) CMOS phased array receiver at 24 GHz, and a 4-element SiGe/CMOS Tx/Rx phased array at 34-38 GHz with 5-bit amplitude and phase control, a 2-antenna 4-simultaneous beam phased array chip at 15 GHz. Also, a miniature 8×8 Butler Matrix with <; 3 dB loss in 0.13 um CMOS has been developed for multibeam applications. It is shown that silicon chips can be used to lower the cost of phased arrays with a significant impact at Ku, K and W-band applications where there is so little available space behind each antenna element due to the very small element area. View full abstract»

An overview is given of some typical radar, ESM and communication systems, based on phased array technology, developed in Italy. A family of S-band, surveillance, 3-dimensional radar systems for air defence applications is presented. The antenna arrays are fed by multiple elevation beam forming and scanning networks. A new active, L-band phased array radar under development will complete the line of the 3D systems. An ECM active phased array antenna is described, as part of a system capable of countering a very large number of simultaneous threats. New developments include a UHF phased array, for zenith coverage of an air defence system, and a quasi-planar array for an air traffic control radar, with adaptive combination of multiple beams in reception for best clutter cancellation. A C-band, full phased-array antenna, with all extremely wide scanning angular sector, adaptive nulling and two-plane, low side lobe, monopulse capability, has been developed for a multifunctional radar for naval application, but with possible utilization, also in fixed and mobile ground systems. Study and design activities are mentioned on an active, X-band phased array for spaceborne SAR applications, where use is made of a single package, multichip hybrid module, as the basic building block View full abstract»

Phase scanning is realized for narrow band phased array by the phase shift method that compensates wave path difference of signified directions. The resolution of the wideband phased array is higher than the narrow phased array. But the frequency band of the wideband phased array is wider. Traditional method can't compensate the wave path difference completely, which causes the beam broadening and the antenna gain decreasing. The phenomenon of """"aperture transition"""" will occur in the case of large scan angle for wideband phased array, which causes the range resolution decreases. A method based on true time delay that compensates the wave path differences of all frequency components within the signal bandwidth is presented in this paper. The wideband linear frequency modulated signal is illustrated to realize true time delay of phased array and demonstrate the effectiveness of the proposed method by computer simulation. The result of computer simulation demonstrates that the wideband passive phased array based on true time delay has the same antenna gain and azimuth resolution with the narrow band phased array and improves the range resolution. View full abstract»

This work presents the design, fabrication and characterization of a 50 MHz Vernier array. The Vernier array was based on a 128 element transducer with half-wavelength pitch, where every third element was used for transmit, every forth element was used for receive and unused elements were left inactive. The array was a forward looking kerfless design based on a PZT-5H substrate with an element-to-element pitch of 19 microns, and the probe was packaged in a 2.5 mm by 3.1 mm endoscopic form factor. The array was fabricated with a single P(VDF-TrFE)-copolymer matching layer and a polymethylpentene (TPX) lens for passive elevation focusing to a depth of 6 mm. To generate beam profiles, images and videos, the transducer was connected to an in-house developed 64-channel, high-frequency phased array beamformer. Near real-time radiation patterns and images were collected at a frame rate of 10 Hz. The performance of the Vernier array was directly compared to that of a previously developed phased array transducer with approximately one-wavelength pitch. Both transducers possessed similar two-way beamformed pulse bandwidths of 60%. At large steering angles the Vernier array suppressed the grating lobe levels 15 dB over the previously developed phased array, however, as a result of the sparseness of the Vernier array, the measured two-way sensitivity was 18.2 dB lower than the phased array with the fully active aperture. Experimental measurements were in good agreement with the theoretical predictions of 20dB grating lobe suppression and 22dB lower sensitivity than the phased array. Comparison images were generated of wire phantoms in a water bath as well as wire phantoms situated in a tissue phantom in order to assess the tradeoff between lower grating lobe levels at the expense of lower sensitivity. View full abstract»

In the free space optical communication system with optical phased array antenna, the performance of acquisition tracking pointing subsystem is affected by the two conflicting performance of optical beam steering precision and optical beam steering range. The novel cascaded optical phased array antenna integrates a programmable phased wedge and an usual optical phased array together. For the novel cascaded optical phased array, it has the function of a phased wedge and an optical phased array with only one liquid crystal device. With theoretical analysis and experiment studying on this novel cascaded optical phased array, the results show that the novel cascaded optical phased array antenna has a good steering precision with the same optical beam steering range of usual optical phased array. View full abstract»

It is generally accepted that a limited-scan antenna system with a phased-array feed uses significantly fewer elements than a direct-radiating, phased-array aperture (planar array) for similar scan coverage. This paper presents an analysis showing this is not necessarily the case. The author derives the relative number of elements for both cases (phased-array fed lens and direct radiating aperture) using two grating lobe conditions: (1) elimination of grating lobes in “real space”; and (2) elimination of grating lobes within the antenna coverage area. The former grating lobe condition does result in fewer array elements for the phased-array feed as expected. But imposing the latter grating lobe condition, often of interest in GEO satellite communication, yields no benefit in element count between a direct-radiating, phased-array aperture and the phased array fed, dual-lens antenna system used in the analysis View full abstract»

A millimetre wave active phased array antenna has been developed that is capable of a wide scanning angle in both the E- and H-planes with small deviation in antenna gain. A dipole antenna with parasitic element has been adopted, which may have the capability of adjusting the influence of mutual coupling in the array element pattern. The design of the parasitic element is examined and the effect of its shape on pattern characteristics is confirmed by experiment. Beam scanning angles of ±57.3 degrees in the E-plane and ±68.2 degrees in the H-plane were obtained for each array antenna pattern View full abstract»

In this paper, we introduce the research activities on phased array antennas over past two decades in the Technical Research and Development Institute (TRDI) of the Japan Defense Agency. Then, we present several examples of the applications of phased array antennas to radar systems by Japan Self Defense forces. The introduction of the research activities includes the development of transmitting and receiving modules for active phased array antennas, the engineering models of array antennas and current efforts on the phased array antennas such as conformal antennas and millimeter wave phased array antennas View full abstract»

In this paper we present a new UWB antenna and its linear phased array. The single UWB element has omnidirectional and stable radiation patterns over a wide-bandwidth that make it suitable for UWB wireless communication. In addition an E-plane phased array design of four proposed UWB antennas has been simulated to achieve beam steering capability which is used in high accuracy phased array radar. Phase of each element applied by the well-known progressive phase shift method. The proposed phased array antenna has a wide beam steering capability of ±30° and an average of -10 dB side lobe level (SLL) in over a wide bandwidth from 3 to 11 GHz. The simulated and measured results of return loss for the single antenna, both single and array Gain, and beam scanning feature will be discussed. The simulation results confirm that the proposed UWB phased array has a stable radiation pattern and perfect cross polar isolation in the entire band of operation for mentioned beam scanning angles. View full abstract»

In this paper, we analyze the performance of the circular phased array transducers for surgical applications. A phased array transducer focuses and steers an acoustic beam by manipulating the phase delay of each transducer electronically. The quality of the intensity distribution of the phased array transducer is assessed primarily by the production of lesion, the intensity in the region proximal to the focal plane, the presence of grating lobes and other secondary maximum. To analyze the performance of phased array transducers, we have developed a computer simulation model to predict the acoustic field intensity in a 3-dimensional space, study the performance of the phased array transducers with different number of elements, elemental radius, medium attenuation, and gap between each element. We have also analyzed and compared the performance of a circular phased array and a square phased array. From our analysis, we note that a circular phased array with 145 elements and 5 mm diameter per element has the most favorable performance in terms of focusing ability and grating lobes. View full abstract»

For microstrip patch phased arrays, larger fractional bandwidth (FBW) and wider scan angle are challenging to achieve at the same time. Phased arrays on thin substrates typically can scan to large angles due to the reduction of mutual coupling caused by surface waves. However, thin substrates limit the achievable FBW of the phased array antenna. In this paper, an integrated filter/patch technology is proposed to realize phased arrays with large scan angle capabilities and enhanced bandwidth. In addition, this integrated filter/patch is able to provide filtering function which is desirable for RF front ends. To prove the concept, a 2^nd-order filter/antenna comprised of one cavity resonator and one patch antenna is designed, fabricated and measured. The center frequency and FBW of the filter/antenna are 5.89 GHz and 5.5%, respectively, with the thickness of the antenna layer being 50 mil. As a comparison, the FBW of a regular coax-fed patch antenna on 50-, 75-, and 100-mil-thick substrates is 2.5%, 4.3%, and 6.3%, respectively. Full-wave Floquet analysis is performed to investigate the active impedance behavior of phased arrays using filter/antenna or patch antennas on substrates with different thickness. It is shown that the filter/antenna phased array exhibits the best performance in terms of active reflection coefficient when the array scans to large angles among all cases. Though the patch antenna phased array on 50-mil-thick substrate has the similar active impedance performance, its FBW (2.5%) is much narrower than that (5.5%) of the filter/antenna phased array. View full abstract»

In order to achieve low sidelobe level for an active phased array antenna, the phase and amplitude distribution of antenna aperture must satisfy design requirements by means of test and calibration. Many methods are presently available for test and calibration of aperture amplitude and phase errors. In this paper, the angle selection relationship sinθ_k=(λ[2k-(L+1)])/2Ld for phased array antenna calibration based on traveling wave technology is proven. We find that if the angle meets the relationship, then the rank of transform matrix is complete and the condition number of transform matrix equals 1, thus, the high precision calibration is achieved. On such a basis, we developed the BIT traveling wave calibration technology for wideband phased array antenna calibration, and named it "dummy internal spacing method", |sinθ_k|>1 mistake in 1-D broadband phased array antenna is avoided. Also, the BIT traveling wave technology can be widely applied to 2-D phased array antenna and non-uniform array antenna easily. By application of the "dummy internal spacing method", we developed 1-D and 2-D phased antennas, and obtained satisfactory results. View full abstract»

A collaborative effort at Texas Tech University on high power RF transmitters has directly translated to the development of phased array pulsed ring down sources (PRDS). By operating an array of PRDS, peak radiating power on target can theoretically be increased to the squared of N sources. The primary limitation on the application of the array concept is the jitter with which the individual sources can be fired. An ideal jitter of a small fraction of the risetime is required to accurately synchronize the array to steer and preserve the amplitude of the radiated pulse. This paper describes in detail the implementation of a GPS based timing system that will synchronize the operation of each of the elements of a geospatially distributed phased array to maximize the peak power delivered to a single position. Theoretical array performance is shown through Monte Carlo simulations, accounting for switch jitter and a range of GPS timing jitter. Each module will include a control unit, low jitter pulser, low jitter spark gap, antenna element, as well as a GPS receiver. The location of each module is transmitted to a central controller, which calculates and dictates when each element is fired. Low jitter in the timing of the GPS reference signal is essential in synchronizing each element to deliver the maximum power. Testing using a preliminary setup using GPS technology is conducted with both 1 pps and 100 pps outputs. Jitter results between modules are recorded to ~10 ns without any correction factors and 1-2 ns with simple averaging. With the timing and geospatial errors taken into account, the proposed concept will show usable gains at phased array operating frequencies up to several hundred MHz. View full abstract»

One of the fundamental features of phased arrays is the ability to focus and steer the propagating waves to a specific point and direction within the load material by inducing a certain time delay. The acoustic characteristic of phased array transducers determine whether the reflective echo can be received. Orthotropic piezoelectric composite materials (OPCM) elements which bears orthotropic function are used to design ultrasonic phased array actuator/senor. A model was developed to compute acoustic pressure distribution of the waves radiated from an ultrasonic linear phased array. Based on the model, beam directivity and focus characteristic were studied for various transducer parameters such as inter-element spacing, element width and number of elements. The focus acoustic field simulation results show that the effects of array elements parameters optimization on directivity are consistent with the one on focus acoustic field, and focus energy enhanced obviously for OPCM elements application. View full abstract»

Phased array antennas offer a number of advantages to the National Aeronautics and Space Administration (NASA) missions compared to traditional gimbaled reflectors including electronic and vibration free beam steering, graceful degradation, smaller volume and multibeam capability. However, the monolithic microwave integrated circuit (MMIC)-based phased array antennas also present challenges to mission designers because of reduced power efficiency, higher costs, and system effects that result in link degradations. The NASA Glenn Research Center (GRC) continues to pioneer aerospace communications technologies to address the challenges of array antennas to improve efficiency, reduce costs [Romanofsky, R., et al., December 2000], and better understand system effects [R. Acosta, et al., May 2002 and S. Johnson et al., June 2002]. This paper addresses the degenerative system effects between high-rate modulated data and signal timing delays caused by antenna beam steering at wide scan angles. Conventional phase shifters used in MMIC-based phased array antennas are physically limited to 360° of phase shift. Often, depending on the size of the array and/or specified beam angle, the required phase shift of some elements may exceed 360°. In these instances, the actual phase shift obtained is the remainder of the phase request, modulo 2π. The modulo 2π result causes a delayed carrier signal radiated from the element whose phase shifter requires a phase shift greater than 360°. Multiple delayed signals radiates from the antenna depending on the size of the array and scan angle. The array antenna system performance described in this report is characterized by measuring the bit error rate (BER) of the link from modulator to demodulator through the phased array antenna across a link inside an anechoic chamber. The array antenna introduces intersymbol interference (ISI) into the link due to the modulo 2π effect of the phase shifters. The ISI is observable in the BER versus Eb/No curve as a "flaring" or additional insertion loss at high Eb/No. Theoretical calculations and computer simulations indicate as much as 3-4 dB degradation due to ISI when the data rate is an appreciable fraction of carrier frequency (>2 Gbps at K- band). Dat- a rates more characteristic of near term systems (e.g. < 1 Gbps) result in somewhat lower losses. Results presented here were obtained for 220 Mbps and 622 Mbps through a K-band (20 GHz), 91-element, phased array antenna. Discussion is provided where results agree and disagree with the simulation results for the data rate and carrier frequency used. View full abstract»

The aim of This paper is to sorting the phased array radar signal. The method is using the radar beams scanning characters of the phased array radar, then proposes an algorithm based on the rough sets theory to sort the signal of phased array radars. From researching on the characters of the phased array radar's beam scanning manners, we can use the PDW received from the receiving equipments as a set of attributes. Through using RST to reduce the attributes of phased array radar signal, we can get the rule of the attributes' nucleus. So we can sort the phased array radar signal from the electromagnet environment from using the rule. Through experiments showed that this method can get a good result and can efficiently sort the phased array radar signal. View full abstract»

Therapeutic ultrasound phased arrays show great promise in the treatment of brain disorders and deep-seated tumors where precise beam steering and controlled power deposition are needed as stated in D. Daum et al. (1999) and G.T. Clement et al. (2000). In addition, cavitation and mechanical effects, which are fast becoming essential elements of these therapies, could potentially be better controlled with phased array systems that employ multi-frequency techniques according to S. Umemura and K. Kawabata (1996) and J.Y. Chapelon et al. (1996). However, these recent therapeutic ultrasound applications increase the demands on the phased array hardware, both the ultrasound transducer and the multi-channel electronic driving system. First, large scale (greater than 200 elements) high-density (elements on the order of 1/2 or less), broadband ultrasound phased array transducers capable of generating high power fields are required. Second, multi-channel amplifier systems that are capable of fully utilizing these large-scale, high-density, broadband arrays need to be developed. With the advent of high power piezocomposites according to T.R. Shrout et al. (1980) and T.R. Gururaja et al. (1980) broadband high-density transducers are now available for therapy; however, the current driving system technology still falls short. In this paper, we describe the design, construction, and evaluation for a multi-channel broadband phased array amplifier system capable of driving large-scale therapeutic phased arrays. View full abstract»

The Configurable Phased Array Demonstrator (CPAD) is a low-cost, reconfigurable, small scale testbed for dual-polarized phased array antenna prototype. It is based on the concept that individual TR modules and radiating elements can be configured in different ways to study the impact of array manifolds on the radiation pattern performance. As an example, a 4 by 4 planar array was constructed with CPAD to support the Multi-Functional Phased Array Radar (MPAR) system developments, and the initial simulation and measurement results of this system are compared. View full abstract»

Summary form only given. High-data-rate, beam-agile, low-profile, compact, and low-power transceiver systems are required to address the air-to-air and satellite communications (SATCOM) connectivity requirements of unmanned assets in the battlefield. To this end, the Ka-band offers a key advantage for smaller size and lower profile antennas over the traditional Xand Ku-band antennas and phased arrays. More importantly, unprecedented continuous bandwidth coverage of tightly-coupled arrays (e.g. J.P. Doane, K. Sertel, and J.L. Volakis, “A wideband, wide scanning tightly coupled dipole array with integrated balun”, IEEE TAP, vol. 61, no. 9, Sept. 2013) that have only recently been demonstrated for RF frequency bands can enable truly disruptive transceivers with continuous coverage of Xthrough Ka-band using a single aperture. Nonetheless, for UWB beam-agile phased-array operation, equally wideband phase-shifters are needed. In this work, we employ the micro electro-mechanical systems (MEMS) phaseshifter technology to develop switched phased-shifters that can be seamlesslyintegrated with the tightly-coupled dipole array elements. A tightly coupled Kaband (25~28 GHz) dipole array antenna with integrated MEMS phase-shifters from XCOM Wireless is presented. In particular, the dipole elements and the feed lines are printed on low-loss alumina (Al2O3) substrate and the phase shifters and the control circuitry are packaged directly into the array unit element, resulting in a compact and low-cost implementation. Each array element requires two phase shifters, in form of differential feed, however, both phase-shifters can be packaged into a single enclosure. To achieve optimum inter-element spacing and element dimensions, full-wave simulations were performed on the array unit cell and the phased-array performance is evaluated using finite array simulations with the integrated phase-shifters. Design and implementation details, as well as the integration approach - nd array performance will be presented. View full abstract»

AThe 60-GHz four-element phased-array transmit/receive (TX/RX) system-in-package antenna modules with phase-compensated techniques in 65-nm CMOS technology are presented. The design is based on the all-RF architecture with 4-bit RF switched LC phase shifters, phase compensated variable gain amplifier (VGA), 4:1 Wilkinson power combining/dividing network, variable-gain low-noise amplifier, power amplifier, 6-bit unary digital-to-analog converter, bias circuit, electrostatic discharge protection, and digital control interface (DCI). The 2 × 2 TX/RX phased arrays have been packaged with four antennas in low-temperature co-fired ceramic modules through flip-chip bonding and underfill process, and phased-array beam steering have been demonstrated. The entire beam-steering functions are digitally controllable, and individual registers are integrated at each front-end to enable beam steering through the DCI. The four-element TX array results in an output of 5 dBm per channel. The four-element RX array results in an average gain of 25 dB per channel. The four-element array consumes 400 mW in TX and 180 mW in RX and occupies an area of 3.74 mm² in the TX integrated circuit (IC) and 4.18 mm² in the RX IC. The beam-steering measurement results show acceptable agreement of the synthesized and measured array pattern. View full abstract»

A 16-element phased-array receiver has been developed for advanced W-band automotive radars. The phased-array receiver is based on a single SiGe chip with RF beamforming capabilities, which is packaged using low-cost bond-wire techniques and attached to a 16-element linear microstrip array. The antenna results in a directivity of 29.3 dB and a gain of 28.0 dB at 77-81 GHz, and can be scanned to ±50^° in the azimuth plane in ~ 1^° steps. The packaging details are presented together with the steps taken to ensure a wideband impedance match and low coupling between the phased-array channels. Gain measurements done at 79 GHz agree well with simulations. The 16-element phased array receiver was used with a 2-element frequency-modulated continuous-wave transmitter at 76.5-77 GHz and high-resolution millimeter-wave images were obtained. The work shows that complex millimeter-wave phased arrays can be packaged using traditional bond-wire techniques, and can be a powerful solution for advanced automotive radars. View full abstract»

This paper will review research-level phased array activities and developed phased array systems in Japan. Two basic technologies for the beamforming networks are discussed, one is microwave processing technology using MMICs and the other is optical processing. Optically controlled phased array antennas utilizing optical components are described. As the commercial available systems, the airborne phased array antenna for INMARSAT-M, and the beam-switching train antenna on the Shinkansen are described. Several systems which have been investigated and not used for the commercial systems are also discussed. These are the S-band beamforming network for inter-satellite links (ISL), the secondary surveillance radar antenna, the multibeam forming network for future mobile satellite systems, and the mechanically steered planar antenna installed on the Shinkasen for DBS View full abstract»