Showing papers on "Phased array published in 2014"

Study and prototyping of practically large-scale mmWave antenna systems for 5G cellular devices

Abstract: This article discusses the challenges, benefits and approaches associated with realizing largescale antenna arrays at mmWave frequency bands for future 5G cellular devices. Key design considerations are investigated to deduce a novel and practical phased array antenna solution operating at 28 GHz with near spherical coverage. The approach is further evolved into a first-of- a-kind cellular phone prototype equipped with mmWave 5G antenna arrays consisting of a total of 32 low-profile antenna elements. Indoor measurements are carried out using the presented prototype to characterize the proposed mmWave antenna system using 16-QAM modulated signals with 27.925 GHz carrier frequency. The biological implications due to the absorbed electromagnetic waves when using mmWave cellular devices are studied and compared in detail with those of 3/4G cellular devices.

Phaser: enabling phased array signal processing on commodity WiFi access points

Abstract: Signal processing on antenna arrays has received much recent attention in the mobile and wireless networking research communities, with array signal processing approaches addressing the problems of human movement detection, indoor mobile device localization, and wireless network security. However, there are two important challenges inherent in the design of these systems that must be overcome if they are to be of practical use on commodity hardware. First, phase differences between the radio oscillators behind each antenna can make readings unusable, and so must be corrected in order for most techniques to yield high-fidelity results. Second, while the number of antennas on commodity access points is usually limited, most array processing increases in fidelity with more antennas. These issues work in synergistic opposition to array processing: without phase offset correction, no phase-difference array processing is possible, and with fewer antennas, automatic correction of these phase offsets becomes even more challenging. We present Phaser, a system that solves these intertwined problems to make phased array signal processing truly practical on the many WiFi access points deployed in the real world. Our experimental results on three- and five-antenna 802.11-based hardware show that 802.11 NICs can be calibrated and synchronized to a 20° median phase error, enabling inexpensive deployment of numerous phase-difference based spectral analysis techniques previously only available on costly, special-purpose hardware.

Experimental circular phased array for generating OAM radio beams

Abstract: A circular phased array antenna that can generate orbital angular momentum (OAM) radio beams in the 10 GHz band is described. The antenna consists of eight inset-fed patch elements and a microstrip corporate feeding network. A full-wave electromagnetic simulator is used to aid the antenna design and theoretical simulations are confirmed by measurements.

A 77–81-GHz 16-Element Phased-Array Receiver With $\pm {\hbox{50}}^{\circ}$ Beam Scanning for Advanced Automotive Radars

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.

Integrated phased array for wide-angle beam steering

Abstract: We demonstrate an on-chip optical phased array fabricated in a CMOS compatible process with continuous, fast (100 kHz), wide-angle (51°) beam-steering suitable for applications such as low-cost LIDAR systems. The device demonstrates the largest (51°) beam-steering and beam-spacing to date while providing the ability to steer continuously over the entire range. Continuous steering is enabled by a cascaded phase shifting architecture utilizing, low power and small footprint, thermo-optic phase shifters. We demonstrate these results in the telecom C-band, but the same design can easily be adjusted for any wavelength between 1.2 and 3.5 μm.

High dielectric antenna array

Abstract: A system and method for wirelessly transmitting signals via antenna phased array. In order to decrease the distance between individual antennae in the array, the antennae are submersed in a high dielectric material in addition to being arranged at right angles to one another, both features precluding one or more antennae from coupling. Furthermore, wires are covered in high dielectric material in order to refract RF signals around them, allowing antennae towards the center of the array to successfully transmit signals past other layers.

Design and analysis of a low-profile 28 GHz beam steering antenna solution for Future 5G cellular applications

Abstract: A first-of-the-kind 28 GHz antenna solution for the upcoming 5G cellular communication is presented in detail. Extensive measurements and simulations ascertain the proposed 28 GHz antenna solution to be highly effective for cellular handsets operating in realistic propagating environments.

Wideband Radar Cross Section Reduction of Slot Antennas Arrays

Abstract: A comprehensive analysis aimed at reducing the radar cross section (RCS) of array antennas, preserving at the same time their radiating performance, is presented. A microstrip slot array is considered as a test case to illustrate the proposed strategy for radar cross section reduction (RCSR). It is shown that a remarkable reduction of the radar signature can be accomplished over a frequency band as wide as two octaves by employing an array of periodic resistive elements in front of the radiating apertures. The monostatic and bistatic RCS of the proposed structures are investigated both for normal and oblique incidence. Different arrangements and geometries of the periodic resistive pattern are thoroughly analyzed showing the benefits and the drawbacks in terms of antenna gain and level of the scattered fields. Furthermore, the use of metallic parasitic elements for enhancing the antenna gain is considered, and the scattering phenomena caused by their presence are addressed, taking into account the appearance of grating lobes. The antenna designs are also analyzed by resorting to a bidimensional color plot presenting the variation of the reradiated field both in frequency and spatial domain. The guidelines illustrated by the proposed examples can be easily applied to other antenna architectures.

Dual function radar communication Time-modulated array

Abstract: This paper introduces the use of Time-modulated array methods to realize a dual function array It is able to do a radar function in the mainlobe, while realizing a communication in the side lobe

Nonuniform Frequency Diverse Array for Range-Angle Imaging of Targets

Abstract: Although phased-array antennas are widely used in communication, radar, and navigation systems, its beampattern is a function of angle only and thus there is no range information. To circumvent this limitation, we design a frequency diverse array (FDA) antenna system for range-angle imaging of targets. Our approach exploits the nonuniform FDA as the transmitter to provide range-dependent beampattern and the uniform phased-array as the receiver which results in angle-dependent beampattern. Range-angle imaging of targets is achieved from the cooperative transmit-receive beamforming. The imaging performance measures including spatial resolution and system processing gain are analyzed. In addition, several design specifications are discussed. The effectiveness of the proposed approach is verified by simulation results.

Large-Scale Silicon Photonic Circuits for Optical Phased Arrays

Abstract: We review recent advances in integrated large-scale optical phased arrays. The design and fabrication of large-scale optical phased arrays using silicon photonic circuits are discussed from device designs including the directional couplers, thermo-optic phase shifters, and optical nanoantennas, to system studies including phased array synthesis and noise analysis. By taking advantage of the well-developed silicon complementary metal-oxide-semiconductor (CMOS) fabrication technology, several large-scale integrated silicon photonic phased arrays are demonstrated, including two passive-phased arrays (64 × 64 and 32 × 32) with the ability to generate complex holographic images, an 8 × 8 active phased array for dynamic optical beamforming, and an 8 × 8 active antenna array with amplitude apodization. These optical phased array demonstrations, with up to 12 000 integrated optical elements, represent the largest and densest silicon photonic circuits demonstrated to date.

Optical phased arrays

Abstract: An optical phased array formed of a large number of nanophotonic antenna elements can be used to project complex images into the far field. These nanophotonic phased arrays, including the nanophotonic antenna elements and waveguides, can be formed on a single chip of silicon using complementary metal-oxide-semiconductor (CMOS) processes. Directional couplers evanescently couple light from the waveguides to the nanophotonic antenna elements, which emit the light as beams with phases and amplitudes selected so that the emitted beams interfere in the far field to produce the desired pattern. In some cases, each antenna in the phased array may be optically coupled to a corresponding variable delay line, such as a thermo-optically tuned waveguide or a liquid-filled cell, which can be used to vary the phase of the antenna's output (and the resulting far-field interference pattern).

Photonic architecture for beam forming of RF phased array antenna

Abstract: System architecture utilizing photonic technology for beam forming of RF phased array antenna is studied. RSOA solution for uplink signal transmission and multi-core fiber approach for two dimensional phased array antenna are demonstrated.

Two-dimensional apodized silicon photonic phased arrays

Abstract: In this Letter, we demonstrate an 8×8 apodized silicon photonic phased array where the emission from each of 64 nanoantennas was tailored to exhibit Gaussian-shaped intensity distributions in the near field so that the sidelobes of the generated far-field optical beam were suppressed compared to that of a uniform phased array. With the aid of the 72 thermo-optic phase tuners directly integrated within the phased array, we dynamically shaped the generated optical beam in the far field in a variety of ways.

Coherent MIMO radar: The phased array and orthogonal waveforms

Abstract: Coherent multiple-input multiple-output (MIMO) radar is a natural extension of the phased array antenna that has been used by radar systems for decades. This tutorial unifies concepts from the literature and provides a framework for the analysis of an arbitrary suite of MIMO radar waveforms. A number of gain patterns are introduced, which quantify the antenna performance of a MIMO radar, and the impact of the waveform characteristics (e.g., range sidelobes) is discussed.

Multiwavelength-Integrated Optical Beamformer Based on Wavelength Division Multiplexing for 2-D Phased Array Antennas

Abstract: A novel, hardware-compressive architecture for broadband and continuously tunable integrated optical truetime- delay beamformers for phased array antennas is proposed and experimentally demonstrated. The novel idea consists in employing the frequency-periodic response of optical ring resonator (ORR) filters in conjunction with on-chip wavelength division multiplexing (WDM), in order to create multiple signal paths on an individual beamformer channel. This novel idea dramatically reduces the network complexity and, in turn, its footprint on the wafer. This allows the integration of an unprecedented number of delay channels on a single chip, ultimately overcoming the main limitation of integrated optical beamformers, that is, the difficulty to feed antenna arrays with many elements using a single integrated chip. A novel beamformer has been realized based on this technique, using the ultra-low-loss TriPleXTM waveguide platform with CMOScompatible fabrication equipment, and its functionality is demonstrated over an instantaneous bandwidth from 2 to 10 GHz. This result, at the best of our knowledge, represents at the same time the record instantaneous bandwidth (8 GHz) for an optical beamformer based on optical ring resonators (ORR), and the first demonstration of an integrated beamformer where the periodic response of ORRs is exploited to process signals from different antenna elements, simultaneously, using a single delay line.

Nonlinear ultrasonic phased array imaging.

Abstract: This Letter reports a technique for the imaging of acoustic nonlinearity. By contrasting the energy of the diffuse field produced through the focusing of an ultrasonic array by delayed parallel element transmission with that produced by postprocessing of sequential transmission data, acoustic nonlinearity local to the focal point is measured. Spatially isolated wave distortion is inferred without requiring interrogation of the wave at the inspection point, thereby allowing nonlinear imaging through depth.

Dual-Band Wide-Angle Scanning Planar Phased Array in X/Ku-Bands

Abstract: A novel planar dual-band phased array, operational in the X/Ku-bands and with wide-angle scanning capability is presented. The design, development and experimental demonstration are described. A new single-layer crossed L-bar microstrip antenna is used for the array design. The antenna has low-profile architecture, measuring only $0.33\lambda \times 0.33\lambda $ , at the low frequency band of operation, with flexible resonance tuning capability offered by the use of a plate-through-hole and field-matching ring arrangement. A 49-element planar (7 $\,\times \,$ 7) array demonstrator has been built and its performance validated, exhibiting good agreement with full-wave simulations. The dual-band array supports a large frequency ratio of nearly 1.8:1, and also maintains good sub-band bandwidths. Wide-angle scanning up to a maximum of 60 $^{\circ}$ and 50 $^{\circ}$ are achieved at the low and high frequency bands of operation, respectively.

Multipath Characteristics of Frequency Diverse Arrays Over a Ground Plane

Abstract: This paper presents a theoretical framework for an analytical investigation of multipath characteristics of frequency diverse arrays (FDAs), a task which is attempted for the first time in the open literature. In particular, transmitted field expressions are formulated for an FDA over a perfectly conducting ground plane first in a general analytical form, and these expressions are later simplified under reasonable assumptions. Developed formulation is then applied to a uniform, linear, continuous-wave operated FDA for the particular case of linear frequency increments, and closed-form solutions are established. Time dependence of the FDA array factor is next eliminated by calculating the average power received by an isotropic antenna at a given observation point. Field and power derivations are repeated for a conventional phased array to establish a performance benchmark. Numerical simulations are conducted for special test cases to demonstrate the advantages of FDAs over conventional phased arrays in terms of multipath propagation.

MIMO-Radar Waveform Covariance Matrix for High SINR and Low Side-Lobe Levels

Abstract: Multiple-input multiple-output (MIMO) radar has better parametric identifiability but compared to phased-array radar, it shows loss in signal-to-noise ratio due to noncoherent processing. To exploit the benefits of both MIMO radar and phased array, a waveform covariance matrix is proposed. To generate the proposed covariance matrix, the values of the cosine function between 0 and π with a step size of π/nT are used to form a positive semi-definite Toeplitz matrix, where nT is the number of transmit antennas. The proposed covariance matrix yields gain in the signal-to-interference-plus-noise ratio (SINR) compared to MIMO radar and have lower sidelobe levels (SLLs) compared to phased-array, MIMO-radar, and the recently proposed phased-MIMO scheme. Moreover, in contrast to the phased-MIMO scheme, where each antenna transmits a different power, our proposed scheme allows same power transmission from each antenna. Simulation results validate our analytical results.

Planar Dual-Band Wide-Scan Phased Array in X-Band

Abstract: The design of a planar dual-band wide-scan phased array is presented. The array uses novel dual-band comb-slot-loaded patch elements supporting two separate bands with a frequency ratio of 1.4:1. The antenna maintains consistent radiation patterns and incorporates a feeding configuration providing good bandwidths in both bands. The design has been experimentally validated with an X-band planar 9 × 9 array. The array supports wide-angle scanning up to a maximum of 60 ° and 50 ° at the low and high frequency bands respectively.

A High-Linearity 76–85-GHz 16-Element 8-Transmit/8-Receive Phased-Array Chip With High Isolation and Flip-Chip Packaging

Abstract: An SiGe transmit-receive phased-array chip has been developed for automotive radar applications at 76-84 GHz. The chip is based on an all-RF beamforming approach and contains 8-transmit channels, 8-receive channels, and a complete built-in-self-test system. Two high-linearity quadrature mixers with an input P1 dB of +2.5 dBm are used and allow simultaneous sum and difference patterns in the receive mode. The chip operates in either a narrowband frequency-modulated continuous-wave (FMCW) mode or a wideband mode with > 2-GHz bandwidth. A high-linearity design results in an input P1 dB of -10 dBm (per channel), a system noise figure of 16-18 dB, and a transmit power is 4-5 dBm (per channel). The chip uses a controlled collapse chip connection (C4) bumping process and is flip-chipped on a low-cost printed-circuit board, and results in > 50-dB isolation between the transmit and receive chains. To our knowledge, this work represents the state-of-the-art in terms of complexity at millimeter-wave frequencies and with simultaneous transmit and receive operation for high-performance FMCW radars.

Fabrication and performance of a miniaturized 64-element high-frequency endoscopic phased array

Abstract: We have developed a 40-MHz, 64-element phased-array transducer packaged in a 2.5 × 3.1 mm endoscopic form factor. The array is a forward-looking semi-kerfed design based on a 0.68Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 (PMN-32%PT) single-crystal wafer with an element-to-element pitch of 38 μm. To achieve a miniaturized form factor, a novel technique of wire bonding the array elements to a polyimide flexible circuit board oriented parallel to the forwardlooking ultrasound beam and perpendicular to the array was developed. A technique of partially dicing into the back of the array was also implemented to improve the directivity of the array elements. The array was fabricated with a single-layer P(VDF-TrFE)-copolymer matching layer and a polymethylpentene (TPX) lens for passive elevation focusing to a depth of 7 mm. The two-way-6-dB pulse bandwidth was measured to be 55% and the average electromechanical coupling (keff) for the individual elements was measured to be 0.62. The one-way -6-dB directivities from several array elements were measured to be ±20°, which was shown to be an improvement over an identical kerfless array. The -3-dB elevation focus resulting from the TPX lens was measured to be 152 μm at the focal depth, and the focused lateral resolution was measured to be 80 μm at a steering angle of 0°. To generate beam profiles and images, the probe was connected to a commercial ultrasound imaging platform which was reprogrammed to allow for phased array transmit beamforming and receive data collection. The collected RF data were then processed offline using a numerical computing script to generate sector images. The radiation pattern for the beamformed transmit pulse was collected along with images of wire phantoms in water and tissue-equivalent medium with a dynamic range of 60 dB. Finally, ex vivo tissue images were generated of porcine brain tissue.

14.6 A scalable THz 2D phased array with +17dBm of EIRP at 338GHz in 65nm bulk CMOS

Abstract: In traditional phased arrays as the number of rows and columns increases, the complexity of array connections and phase shifters becomes a major obstacle. This challenge is even more detrimental at mm-Wave and THz frequencies where conductive loss, undesired couplings, phase/gain mismatch, and high power consumption are among many adverse effects of such lengthy connections. To address this issue, this work presents a novel scalable system for THz signal generation and radiation. Figure 14.6.1 shows the architecture consisting of a 2-D array of coupled oscillating elements. Each oscillator with its antenna forms a small THz radiator. While independently radiating, each element is also unidirectionally connected to its neighboring elements in both horizontal and vertical directions through variable phase shifters, ψrow and ψcol, respectively. This network is inherently scalable because it only relies on couplings with the nearest neighbors and there is no high-frequency global routing to any oscillator. The purpose of this topology is twofold: first to synchronize all the oscillators to a single frequency and next, to set a desired phase shift between the adjacent elements (Δφrow and Δφcol). We can show that by employing this particular coupling structure only a small subset of all the theoretical coupling modes are physically stable. By proper control of the couplings one can ensure the system settles into the desired coupling mode [1].

Solid state optical phased array lidar and method of using same

Abstract: A lidar-based apparatus and method are used for the solid state steering of laser beams using Photonic Integrated Circuits. Integrated optic design and fabrication micro- and nanotechnologies are used for the production of chip-scale optical splitters that distribute an optical signal from a laser essentially uniformly to an array of pixels, said pixels comprising tunable optical delay lines and optical antennas. Said antennas achieve out-of-plane coupling of light. As the delay lines of said antenna-containing pixels in said array are tuned, each antenna emits light of a specific phase to form a desired far-field radiation pattern through interference of these emissions. Said array serves the function of solid state optical phased array. By incorporating a large number of antennas, high-resolution far-field patterns can be achieved by an optical phased array, supporting the radiation pattern beam forming and steering needed in solid state lidar, as well as the generation of arbitrary radiation patterns as needed in three-dimensional holography, optical memory, mode matching for optical space-division multiplexing, free space communications, and biomedical sciences. Whereas imaging from an array is conventionally transmitted through the intensity of the pixels, the optical phased array allows imaging through the control of the optical phase of pixels that receive coherent light waves from a single source.

Wideband antenna array for Simultaneous Transmit and Receive (STAR) applications

Abstract: A wideband antenna array for Simultaneous Transmit and Receive (STAR) applications is presented. The design is comprised of a ring array of TEM horns, and a monocone at the array's center. When the array is phased with the first order circular mode, it is isolated from the monocone. Thus, the array may be used in reception while the monocone is used in transmission, or vice versa. The array and monocone both produce quasi-omnidirectional patterns in the azimuthal planes. Simulations suggest that the design operates across an 8.4 : 1 bandwidth. This wide bandwidth is possible through the use of a novel capacitive feed employed in the TEM horn array.

Directional multiband antenna

Abstract: There is disclosed a directional multi-band antenna comprising a substrate structure, a plurality of RF units arranged at the substrate structure to provide an RF phased array, the RF phased array having an angular scan range, an array of optical units arranged at the substrate structure and interspersed amongst the RF units, an array of optical lensing devices supported over the substrate structure, the array of optical lensing devices being substantially RF transmissive and being arranged to correspond with the arrangement of the optical units, such that each optical unit may communicate light signals with an associated optical lensing device so as to communicate light signals along an optical axis within the angular scan range of the RF phased array

High frequency piezoelectric micromachined ultrasonic transducer array for intravascular ultrasound imaging

Abstract: This paper presents a 1.2 mm diameter high fill-factor array of 1,261 piezoelectric micromachined ultrasonic transducers (PMUTs) operating at 18.6 MHz for intravascular ultrasound (IVUS) imaging and other medical imaging applications. At 1061 transducers/mm2, the PMUT array has a 10-20× higher density than the best PMUT arrays realized to date. The PMUTs utilize a piezoelectric material, AlN, which is compatible with CMOS processes. Measurements show a large voltage response of 2.5 nm/V and good frequency matching in air, a high center frequency of 18.6 MHz and wide bandwidth of 4.9 MHz when immersed in fluid. Phased array simulations based on measured PMUT parameters show a tightly focused, high output pressure acoustic beam.

A compact 4-chip package with 64 embedded dual-polarization antennas for W-band phased-array transceivers

Abstract: A fully-integrated antenna-in-package (AiP) solution for W-band scalable phased-array systems is demonstrated We present a fully operational compact W-band transceiver package with 64 dual-polarization antennas embedded in a multilayer organic substrate This package has 12 metal layers, a size of 162 mm × 162 mm, and 292 ball-grid-array (BGA) pins with 04 mm pitch Four silicon-germanium (SiGe) transceiver ICs are flip-chip attached to the package Extensive full-wave electromagnetic simulation and radiation pattern measurements have been performed to optimize the antenna performance in the package environment, with excellent model-to-hardware correlation achieved Enabled by detailed circuit-package co-design, a half-wavelength spacing, ie, 16 mm at 94 GHz, is maintained between adjacent antenna elements to support array scalability at both the package and board level Effective isotropic radiated power (EIRP) and radiation patterns are also measured to demonstrate the 64-element spatial power combining

A 160 GHz Pulsed Radar Transceiver in 65 nm CMOS

Abstract: This paper presents a 160 GHz center frequency pulsed 65 nm CMOS transceiver for short range radar applications. Four phased array transceivers were implemented in a single chip with antennas implemented in a BGA package. The implemented transmitter is capable of producing pulses of 100 ps widths ( >20 GHz RF bandwidth) at a 160 GHz carrier frequency. The measured effective isotropic radiated power (EIRP) is 18.8 dBm for continuous wave outputs. The analog beam forming receiver achieves an overall gain of 42.5 dB, -14 dBm IP1dB, 7 GHz bandwidth, and a noise figure of 22.5 dB. The sliding window time-dilation baseband relaxes the output data rate and subsequent digital processing requirements. Fine grained duty cycling reduces power dissipation. The entire chip consumes 2.2 W from 1.2/1.4 V supplies in a 65 nm digital CMOS process.