Showing papers on "Phased array published in 2018"

A Low-Cost Scalable 32-Element 28-GHz Phased Array Transceiver for 5G Communication Links Based on a $2\times 2$ Beamformer Flip-Chip Unit Cell

Abstract: This paper presents a scalable 28-GHz phased-array architecture suitable for fifth-generation (5G) communication links based on four-channel ( $2\times 2$ ) transmit/receive (TRX) quad-core chips in SiGe BiCMOS with flip-chip packaging. Each channel of the quad-core beamformer chip has 4.6-dB noise figure (NF) in the receive (RX) mode and 10.5-dBm output 1-dB compression point (OP1dB) in the transmit (TX) mode with 6-bit phase control and 14-dB gain control. The phase change with gain control is only ±3°, allowing orthogonality between the variable gain amplifier and the phase shifter. The chip has high RX linearity (IP1dB = −22 dBm/channel) and consumes 130 mW in the RX mode and 200 mW in the TX mode at P1dB per channel. Advantages of the scalable all-RF beamforming architecture and circuit design techniques are discussed in detail. 4- and 32-element phased-arrays are demonstrated with detailed data link measurements using a single or eight of the four-channel TRX core chips on a low-cost printed circuit board with microstrip antennas. The 32-element array achieves an effective isotropic radiated power (EIRP) of 43 dBm at P1dB, a 45-dBm saturated EIRP, and a record-level system NF of 5.2 dB when the beamformer loss and transceiver NF are taken into account and can scan to ±50° in azimuth and ±25° in elevation with < −12-dB sidelobes and without any phase or amplitude calibration. A wireless link is demonstrated using two 32-element phased-arrays with a state-of-the-art data rate of 1.0–1.6 Gb/s in a single beam using 16-QAM waveforms over all scan angles at a link distance of 300 m.

A 28GHz Bulk-CMOS dual-polarization phased-array transceiver with 24 channels for 5G user and basestation equipment

Abstract: Developing next-generation cellular technology (5G) in the mm-wave bands will require low-cost phased-array transceivers [1]. Even with the benefit of beamforming, due to space constraints in the mobile form-factor, increasing TX output power while maintaining acceptable PA PAE, LNA NF, and overall transceiver power consumption is important to maximizing link budget allowable path loss and minimizing handset case temperature. Further, the phased-array transceiver will need to be able to support dual-polarization communication. An IF interface to the analog baseband is desired for low power consumption in the handset or user equipment (UE) active antenna and to enable use of arrays of transceivers for customer premises equipment (CPE) or basestation (BS) antenna arrays with a low-loss IF power-combining/splitting network implemented on an antenna backplane carrying multiple tiled antenna modules.

A 64-Element 28-GHz Phased-Array Transceiver With 52-dBm EIRP and 8–12-Gb/s 5G Link at 300 Meters Without Any Calibration

Abstract: This paper presents a 64-element 28-GHz phased-array transceiver for 5G communications based on $2\times 2$ transmit/ receive (TRX) beamformer chips. Sixteen of the $2\times 2$ TRX chips are assembled on a 12-layer printed circuit board (PCB) together with a Wilkinson combiner/divider network and 28–32-GHz stacked-patch antennas. The 64-element array results in 1.1 dB and 8.9° rms amplitude and phase error, respectively, with no calibration due to the symmetric design of the $2\times 2$ beamformer chips and the PCB Wilkinson network. The effect of phase and amplitude mismatch between the 64 elements is analyzed and shown to have little impact on the 64-element array performance due to the averaging effects of phased arrays. Detailed pattern, effective isotropic radiated power (EIRP), and link measurements performed without any array calibration are presented and show the robustness of the symmetrical design technique. The phased array can scan to ±50° in azimuth ( $H$ -plane) and ±25° in elevation ( $E$ -plane) with low sidelobes and achieves a saturated EIRP of 52 dBm with 4-GHz 3-dB bandwidth. A 300-m wireless link is demonstrated with a record-setting data rate of 8–12 Gb/s over all scan angles using two 64-element TRX arrays and 16-/64-QAM waveforms.

A Monolithically Integrated Large-Scale Optical Phased Array in Silicon-on-Insulator CMOS

Abstract: A large-scale monolithic silicon nanophotonic phased array on a chip creates and dynamically steers a high-resolution optical beam in free space, enabling emerging applications in sensing, imaging, and communication. The scalable architecture leverages sub-array structure, mitigating the impact of process variation on the phased array performance. In addition, sharing control electronics among multiple optical modulators in the scalable architecture reduces the number of digital-to-analog converters (DACs) required for an $N^{2}$ array from $\mathcal {O}(N^{2})$ to $\mathcal {O}(N)$ , allowing a small silicon footprint. An optical phased array for 1550-nm wavelength with 1024 uniformly spaced optical grating antennas, 1192 optical variable phase shifters, and 168 optical variable attenuators is integrated into a 5.7 mm $\times$ 6.4 mm chip in a commercial 180-nm silicon-on-insulator RF CMOS technology. The control signals for the optical variable phase shifters and attenuators are provided by 136 DACs with 14-bit nonuniform resolution using 2.5-V input-output transistors. The implemented phased array can create 0.03° narrow optical beams that can be steered unambiguously within ±22.5°.

A Novel 28 GHz Beam Steering Array for 5G Mobile Device With Metallic Casing Application

Abstract: The design of a novel practical 28 GHz beam steering phased array antenna for future fifth generation mobile device applications is presented in this communication. The proposed array antenna has 16 cavity-backed slot antenna elements that are implemented via the metallic back casing of the mobile device, in which two eight-element phased arrays are built on the left- and right-side edges of the mobile device. Each eight-element phased array can yield beam steering at broadside and gain of >15 dBi can be achieved at boresight. The measured 10 dB return loss bandwidth of the proposed cavity-backed slot antenna element was approximately 27.5–30 GHz. In addition, the impacts of user’s hand effects are also investigated.

Photonic microwave true time delays for phased array antennas using a 49 GHz FSR integrated optical micro-comb source [Invited]

Abstract: We demonstrate significantly improved performance of a microwave true time delay line based on an integrated optical frequency comb source. The broadband micro-comb (over 100 nm wide) features a record low free spectral range (FSR) of 49 GHz, resulting in an unprecedented record high channel number (81 over the C band)—the highest number of channels for an integrated comb source used for microwave signal processing. We theoretically analyze the performance of a phased array antenna and show that this large channel count results in a high angular resolution and wide beam-steering tunable range. This demonstrates the feasibility of our approach as a competitive solution toward implementing integrated photonic true time delays in radar and communications systems.

Photonic RF and microwave reconfigurable filters and true time delays based on an integrated optical Kerr frequency comb source

Abstract: We demonstrate advanced transversal radio frequency (RF) and microwave functions based on a Kerr optical comb source generated by an integrated micro-ring resonator. We achieve extremely high performance for an optical true time delay aimed at tunable phased array antenna applications, as well as reconfigurable microwave photonic filters. Our results agree well with theory. We show that our true time delay would yield a phased array antenna with features that include high angular resolution and a wide range of beam steering angles, while the microwave photonic filters feature high Q factors, wideband tunability, and highly reconfigurable filtering shapes. These results show that our approach is a competitive solution to implementing reconfigurable, high performance and potentially low cost RF and microwave

Advanced RF and microwave functions based on an integrated optical frequency comb source.

Abstract: We demonstrate advanced transversal radio frequency (RF) and microwave functions based on a Kerr optical comb source generated by an integrated micro-ring resonator. We achieve extremely high performance for an optical true time delay aimed at tunable phased array antenna applications, as well as reconfigurable microwave photonic filters. Our results agree well with theory. We show that our true time delay would yield a phased array antenna with features that include high angular resolution and a wide range of beam steering angles, while the microwave photonic filters feature high Q factors, wideband tunability, and highly reconfigurable filtering shapes. These results show that our approach is a competitive solution to implementing reconfigurable, high performance and potentially low cost RF and microwave signal processing functions for applications including radar and communication systems.

A 60-GHz 144-Element Phased-Array Transceiver for Backhaul Application

Abstract: A 144-element phased array transceiver is realized using a modular tiled approach that supports 802.11ad, MCS12 single carrier 16-quadratic-amplitude modulation (QAM) 4.6 Gbps, in the 60-GHz band. It consists of a system-on-a chip (SOC) (MAC/PHY/BB to IF) in 28-nm CMOS, and one IF-to-60-GHz transceiver master chip driving twelve 60-GHz phased array transceiver slave chips fabricated in a 40-nm CMOS. Using the master-slave configuration, the 60-GHz transceiver with 12 phase-controlled TX/RX slices is expanded to 144 phase-controlled slices. Each final TX/RX slice is then connected to two patch antennas on LTCC substrate. A tiled approach is used to create the 288 patch antenna array out of six identical tiles each with two slave 60-GHz transceivers connected to a 48-element antenna array. The single tile phased array with 48 antennas has a measured beam steering scan angle of 60° in azimuth and 10° in elevation. The full phased array transceiver with 288 antennas has a measured over the air (OTA) max effective isotropic radiated power (EIRP) of 51 dBm at saturated power (PSAT), and EIRP of 44.8 dBm with −22 dB EVM for MCS12 (16QAM-4.6 Gbps) at broadside. It has an OTA measured sensitivity of −87.3 and −80.4 dBm for MCS9 (QPSK-2.5 Gbps) and MCS12, respectively, at broadside. A packet error rate of 10−5 was measured for MCS9 and MCS12 with an OTA input power of −85 and −77.5 dBm, respectively, for the full phased array transceiver at broadside.

Ultraino: An Open Phased-Array System for Narrowband Airborne Ultrasound Transmission

Abstract: Modern ultrasonic phased-array controllers are electronic systems capable of delaying the transmitted or received signals of multiple transducers. Configurable transmit–receive array systems, capable of electronic steering and shaping of the beam in near real-time, are available commercially, for example, for medical imaging. However, emerging applications, such as ultrasonic haptics, parametric audio, or ultrasonic levitation, require only a small subset of the capabilities provided by the existing controllers. To meet this need, we present Ultraino, a modular, inexpensive, and open platform that provides hardware, software, and example applications specifically aimed at controlling the transmission of narrowband airborne ultrasound. Our system is composed of software, driver boards, and arrays that enable users to quickly and efficiently perform research in various emerging applications. The software can be used to define array geometries, simulate the acoustic field in real time, and control the connected driver boards. The driver board design is based on an Arduino Mega and can control 64 channels with a square wave of up to 17 Vpp and $\pi $ /5 phase resolution. Multiple boards can be chained together to increase the number of channels. The 40-kHz arrays with flat and spherical geometries are demonstrated for parametric audio generation, acoustic levitation, and haptic feedback.

Microcomb-Based True-Time-Delay Network for Microwave Beamforming With Arbitrary Beam Pattern Control

Abstract: Microwave phased array antennas (PAAs) are very attractive to defense applications and high-speed wireless communications for their abilities of fast beam scanning and complex beam pattern control. However, traditional PAAs based on phase shifters suffer from the beam-squint problem and have limited bandwidths. True-time-delay (TTD) beamforming based on low-loss photonic delay lines can solve this problem. But it is still quite challenging to build large-scale photonic TTD beamformers due to their high hardware complexity. In this paper, we demonstrate a photonic TTD beamforming network based on a miniature microresonator frequency comb (microcomb) source and dispersive time delay. A method incorporating optical phase modulation and programmable spectral shaping is proposed for positive and negative apodization weighting to achieve arbitrary microwave beam pattern control. The experimentally demonstrated TTD beamforming network can support a PAA with 21 elements. The microwave frequency range is 8-20 GHz; and the beam scanning range is ±60.2°. Detailed measurements of the microwave amplitudes and phases are performed. The beamforming performances of Gaussian, rectangular beams, and beam notch steering are evaluated through simulations by assuming a uniform radiating antenna array. The scheme can potentially support larger PAAs with hundreds of elements by increasing the number of comb lines with broadband microcomb generation.

Contactless Fluid Manipulation in Air: Droplet Coalescence and Active Mixing by Acoustic Levitation.

Abstract: Acoustic manipulation by an ultrasonic phased array provides an entirely new approach to processes such as coalescence, mixing, separation, and evaporation occurring in the generation of new materials, physical property measurement, the biomedical industry, etc. However, to date, ultrasonic phased arrays have not been fully investigated for applications in fluid manipulation. This paper provides contactless coalescence and mixing techniques for droplets in air by controlling the acoustic potential by using an ultrasonic phased array. We focused on mode oscillation to propose an efficient mixing technique for liquid without contact. A comparison of mixing performance between cases with mode oscillation and without mode oscillation showed that the flow induced by mode oscillation promotes droplet mixing. Our paper demonstrates the feasibility of contactless coalescence and mixing as a first step in fluid manipulation with a phased array.

Compact Quad-Mode Planar Phased Array With Wideband for 5G Mobile Terminals

Abstract: In this paper, a quad-mode endfire planar phased antenna array with wide scan angle and 1.2 mm clearance is proposed for 5G mobile terminals. The proposed antenna can obtain over 8 GHz of impedance bandwidth. In this paper, it is suggested to efficiently combine a multimode array element with different radiation patterns for each mode into a phased antenna array. In the array, similar and wide embedded radiation patterns are obtained for the all four modes. Furthermore, a coaxial to differential stripline transition is designed in this paper. The differential feeding structure is very compact and utilizes only MMPX connector and vias. The total scan pattern and coverage efficiency of the measured and simulated phased array antenna are calculated in the range from 25 to 33 GHz, and good agreement between measured and simulated results is observed. The mean coverage efficiency along the frequency range is very similar, but minor difference in variance of coverage efficiency is observed in the measurements. The coverage efficiency of around 50% for the threshold gain of 5 dBi is achieved in the chosen frequency range.

Study on Wide-Angle Scanning Linear Phased Array Antenna

Abstract: Two wide-angle scanning linear array antennas (E- and H-planes scanning linear array antenna) are studied and presented. In order to improve the wide-angle scanning performance of the phased array antenna, a wide beamwidth U-shaped microstrip antenna with the electric walls is designed. The wide-angle scanning linear array antennas are studied in the frequency band from 3.2 to 3.8 GHz. The 3 dB beamwidth of the antenna is 140° in the E-plane scanning linear array center and 220° in the H-plane scanning linear array center at 3.5 GHz. The main beams of the H-plane scanning linear array antenna can scan from −90° to +90° with a gain fluctuation less than 3 dB and a maximum sidelobe level (SLL) less than −5 dB. Simultaneously, the main beam of the E-plane scanning linear array antenna can scan from −75° to +75° with a gain fluctuation less than 3 dB and SLL less than −5 dB. The H- and E-planes scanning linear array antennas with nine elements are fabricated and tested. The measured results have a good agreement with the simulation results.

Experimental demonstration of conformal phased array antenna via transformation optics

Abstract: Transformation Optics has been proven a versatile technique for designing novel electromagnetic devices and it has much wider applicability in many subject areas related to general wave equations. Among them, quasi-conformal transformation optics (QCTO) can be applied to minimize anisotropy of transformed media and has opened up the possibility to the design of broadband antennas with arbitrary geometries. In this work, a wide-angle scanning conformal phased array based on all-dielectric QCTO lens is designed and experimentally demonstrated. Excited by the same current distribution as such in a conventional planar array, the conformal system in presence of QCTO lens can preserve the same radiation characteristics of a planar array with wide-angle beam-scanning and low side lobe level (SLL). Laplace’s equation subject to Dirichlet-Neumann boundary conditions is adopted to construct the mapping between the virtual and physical spaces. The isotropic lens with graded refractive index is realized by all-dielectric holey structure after an effective parameter approximation. The measurements of the fabricated system agree well with the simulated results, which demonstrate its excellent wide-angle beam scanning performance. Such demonstration paves the way to a robust but efficient array synthesis, as well as multi-beam and beam forming realization of conformal arrays via transformation optics.

Ultra-Wideband Phased Array for Millimeter-Wave ISM and 5G Bands, Realized in PCB

Abstract: In this paper, we present the design, fabrication, and measurement of an ultra-wideband phased array antenna, with continuous coverage of all six allocated fifth generation and industrial, scientific, medical bands in the millimeter-wave spectrum. Of importance is that the complete array is co-fabricated as a single printed circuit board using commercial processes, implying a significant reduction in cost over previous microfabrication-based designs. The design is demonstrated in simulation to operate across 24–72 GHz with VSWR $3\times 3$ array prototype, which shows close agreement to the simulated values.

Hybrid MIMO and Phased-Array Directional Modulation for Physical Layer Security in mmWave Wireless Communications

Abstract: Millimeter-wave (mmWave) wireless communication system allows a compact antenna array with a large number of colocated elements, which enables flexible array design and beampattern synthesis. However, security is also particularly important but challenging for the fifth-generation (5G) wireless communications, as the broadcasting nature allows any receivers to have a copy of the transmitted signals. In this paper, we propose a hybrid multiple-input multiple-output (MIMO) phased-array time-modulated directional modulation (DM) scheme for physical layer security in mmWave wireless communications. The hybrid MIMO phased-array enjoys the advantages of MIMO in spatial diversity without sacrificing the main advantage of phased-array in coherent directional gain. The essence is to divide the transmit array into multiple subarrays. Each subarray can be used to form a directional beam, while all subarrays are jointly combined to work as an MIMO for higher angular resolution capabilities. More importantly, a time-modulated DM scheme is applied for the phased-MIMO to achieve physical layer security for mmWave wireless communications, even without the knowledge of the eavesdropper’s position information. The feasibility of the proposed scheme is verified by numerical results.

On-chip platform for a phased array with minimal beam divergence and wide field-of-view.

Abstract: Current silicon photonics phased arrays based on waveguide gratings enable beam steering with no moving parts. However, they suffer from a trade-off between beam divergence and field of view. Here, we show a platform based on silicon-nitride/silicon that achieves simultaneously minimal beam divergence and maximum field of view while maintaining performance that is robust to fabrication variations. In addition, in order to maximize the emission from the entire length of the grating, we design the grating's strength by varying its duty cycle (apodization) to emit uniformly. We fabricate a millimeter long grating emitter with diffraction-limited beam divergence of 0.089°.

Development of frequency diverse array radar technology: a review

Abstract: Electronic beam steering with greater efficiency is a vibrant feature of a phased array antenna, but for all the range cells, it is fixed at a specific angle. To mitigate this problem, frequency diverse array (FDA) antenna was proposed. This study presents a review on the development of FDA technology in radar and navigation applications. FDA is different from a conventional phased array antenna radar in a sense that it uses a small frequency offset across the array, which helps to generate a range, angle and time-dependent beam pattern. This pattern assures the energy transmission towards the desired angle and range cell. In addition, this study also focuses the research on getting range-angle uncoupled beam patterns along with diverse hybrid cognitive FDA design, available in the literature, for improved radar performance.

A 16-Element W-Band Phased-Array Transceiver Chipset With Flip-Chip PCB Integrated Antennas for Multi-Gigabit Wireless Data Links

Abstract: This paper describes the design and implementation of a W-band phased-array system with printed circuit board (PCB) integrated antennas in two polarizations capable of multi-gigabit spectrally efficient wireless communication. The chipset is manufactured in a 0.18- $\mu \text{m}$ SiGe BiCMOS technology with $f_{T}/f_{\mathrm {MAX}}$ of 240-/270-GHz and is flip-chipped onto a low-cost organic PCB with integrated antenna arrays. Each chip is equipped with 16-transmit/4-receive or 16-receive/4-transmit calibrated phase shifter elements and direct up- and downconverters plus a half-rate phase-locked loop. The different system tradeoffs required to establish a multi-Gb/s wireless link at millimeter waves are carefully studied. Built-in element failure detectors, power detectors, and digital interface enable factory calibration and self-test capability. Each transceiver chip operates from 1.5- and 2.5-V supplies and consumes 5.5 and 4.5 W in transmit and receive mode, respectively. The peak transmitter effective isotropic radiation power is 34 dBm in each polarization with a measured receiver noise figure of 6.5 dB at 94 GHz. At a distance of 1 m, a maximum wireless data rate of 30 Gb/s (per polarization) using 64-QAM can be achieved and at 20 m, 8 Gb/s (dual polarization) can be established using QPSK modulation.

63.5–65.5-GHz Transmit/Receive Phased-Array Communication Link With 0.5–2 Gb/s at 100–800 m and ± 50° Scan Angles

Abstract: This paper presents a 32-element phased array centered at 64 GHz using multiple SiGe chips on a single printed-circuit board. The antenna element is a series-fed patch array, which provides directivity in the elevation plane. The transmit array results in an effective isotropic radiated power of 42± 2 dBm at 63–65.5 GHz, while the receive array provides an electronic gain of 24 dB and a system noise figure <7.7 dB, including antenna loss, T/R switch, beamformer, and transceiver. The arrays can be scanned to ±50° in the azimuth using a 5-bit phase shifter on the SiGe chip without degradation in sidelobes and maintaining a near-ideal pattern. A communication link between two phased arrays at 100, 300, and 800 m is also demonstrated, and employs one array on the transmit side and another array on the receive side, together with external mixers and IF amplifiers. The link performance was measured for different scan angles and modulation formats. Data rates of 0.5–2 Gb/s using 16-QAM and QPSK waveforms are demonstrated at 100–800 m, with 2-Gb/s data rate at 300 m and ~500-Mb/s data rate at 800 m. To the best of our knowledge, this is the first system-level demonstration of a silicon-based Gb/s 60-GHz phased array over hundreds of meters. Application areas are in point-to-multipoint links, back-haul and front-haul links, and reconfigurable mesh networks for advanced communication systems.

High-Isolation, Low Cross-Polarization, Dual- Polarization, Hybrid Feed Microstrip Patch Array Antenna for MPAR Application

Abstract: This paper presents a high-isolation, low cross-polarization dual-polarized patch antenna for multifunction phased array radar applications. Its hybrid feed design has been implemented, and the vertical and horizontal polarizations are excited by a balanced-probe feed and a slot-coupled feed, respectively. Simulations and measurements have demonstrated an input isolation of 45 and 43 dB between the horizontal and vertical ports, respectively. For further improvement in the cross-polarization level, the image feed method is also implemented, and a $2\times 2$ -element array made up of designed elements with image configuration has been fabricated. The simulated and measured S-parameter and radiation patterns of the horizontal and vertical polarizations of the designed $2\times 2$ -element array are presented and the measured cross-polarization level of less than −37 dB is achieved. To examine the performance of the designed element in an array, a $3\times 3$ -element array of designed $2\times 2$ -element subarray is fabricated and tested. In the $6\times 6$ -element measurements, −35.4 and −36 dB cross-polarization levels for horizontal and vertical polarizations are achieved, respectively. Also, using the measured embedded element patterns, the cross-polarization level lower than −36 dB for scan angles up to 45° is achieved.

Wideband RF Self-Interference Cancellation Circuit for Phased Array Simultaneous Transmit and Receive Systems

Abstract: With the growing demand for spectrum utilization, the concept of full duplex transceivers has become attractive. These simultaneous transmit and receive systems (STAR) are attractive as they double bandwidth utilization. To realize STAR, we must suppress self-interference (SI) between transmit and receive antennas. Doing this across a wide bandwidth presents an even greater challenge. Further, for antenna arrays, SI can be higher due to mutual coupling among neighboring elements. In this paper, we achieve 100 dB isolation for practical STAR, across a large 500 MHz bandwidth. Specifically, four stages of the self-interference cancellation are proposed. In addition to high isolation cross-polarized array elements, we employ multi-tap filters at the transceiver RF front-end for interference cancellation. These filters emulate direct SI coupling using frequency-domain optimization techniques. Measured results show an average of 25 dB filter cancellation is possible across 500 MHz.

A Cross-Stacked Radiating Antenna With Enhanced Scanning Performance for Digital Beamforming Multifunction Phased-Array Radars

Abstract: This contribution presents the results of a dual-polarized radiating element designed to achieve low cross-polarization (lower than −40 dB measured for the E-and H-plane, at least −30 dB in the D-plane based on simulations) and large fractional bandwidth (18%) over wide scanning angles (±60°). The proposed design includes multiple features that enable high isolation between ports, reduction of spurious radiation, highly symmetrical radiated fields, and suppression of diffracted fields between contiguous subarray gaps. To verify the polarimetric requirements for a weather radar, simulated and measured results, including electronic scanning of the array and embedded element patterns of the antenna, are shown.

Low-Loss Continuously Tunable Optical True Time Delay Based on Si3N4 Ring Resonators

Abstract: We design, fabricate, and characterize ultra-low loss continuously tunable optical true time delay devices based on Si3N4 ring resonators in a side-coupled integrated spaced sequence of resonators (SCISSOR) structure. A large tunable delay range up to 3.4 ns is demonstrated using the Balanced SCISSOR delay tuning scheme, for a record loss of only 0.89 dB/ns of delay. By optimizing the coupler design a device delay bandwidth of over 10 GHz is achieved with over 0.5 ns maximum time delay. This ultra-low loss delay line can enable distortion free operation for RF signals used in RF beamforming and other applications. Additionally, this device has the potential to be integrated with active photonic components to be part of a fully integrated photonic integrated circuit in an electronically scanned phased array system; utilizing a silicon photonics platform including heterogeneous integration.

Integrated visible light phased array system for autostereoscopic image projection.

Abstract: We demonstrate a chip-scale autostereoscopic image projection system that utilizes a system of multiple integrated visible light optical phased arrays to reconstruct virtual light fields Each phased array in this system serves as a micro-projector that illuminates the desired virtual object from a different angle This recreates the virtual object in space with continuous parallax observable by the human visual system In this work, a static virtual image with horizontal parallax and a viewing angle of 5° was generated with an array of 16 integrated silicon nitride phased arrays with a 635 nm operating wavelength Each phased array is comprised of 32×32 optical antennas with passively encoded relative phases The presented device demonstrates the promise of integrated visible light phased array platforms for implementing projection-based autostereoscopic displays in compact chip-scale platforms suitable for mobile devices

512-Element Actively Steered Silicon Phased Array for Low-Power LIDAR

Abstract: We demonstrate the highest yet-reported element count actively-steered optical phased array with record low array power consumption of <1.8W. We show 2D steering over a 70 × 14 degree field of view while pumped by an integrated InP/silicon laser.

LiSteer: mmWave Beam Acquisition and Steering by Tracking Indicator LEDs on Wireless APs

Abstract: We present LiSteer, a novel system that steers mmWave beams at mobile devices by repurposing indicator LEDs on wireless Access Points (APs) to passively acquire direction estimates using off-the-shelf light sensors. We demonstrate that LiSteer maintains beam alignment at the narrowest beamwidth level even in case of device mobility, without incurring any training overhead at mobile devices. Our extensive evaluation on a custom dual-band hardware platform comprising highly directional horn antennas as well as practical phased antenna arrays with electronic beam steering shows that LiSteer achieves direction estimates within 2.5 degrees of ground truth on average. Moreover, it achieves beam steering accuracy of more than 97% while in tracking mode, without incurring any client beam training or feedback overhead.

An Extended $4 \times 4$ Butler Matrix With Enhanced Beam Controllability and Widened Spatial Coverage

Abstract: A new beam-switching array system, capable of providing four sets of switchable beams, is proposed and demonstrated. The core building block for fulfilling the design is the phase reconfigurable synthesized transmission line (PRSTL), whose electrical length is switched between two states as a 1-bit phase shifter. By cascading the PRSTLs to the outputs of a standard Butler matrix, the progressive phase shifts between adjacent antenna elements can be controlled in a variety of fashions. The new design aims to provide a low-complexity solution to expand the beam controllability as well as spatial coverage of a conventional beam-switching system. As a demonstration, an extended $4 \times 4$ Butler matrix, with 16 switchable beams, is realized using microstrip technology. The average transmission loss of the feed network is acceptable as 1.7 dB. In the measurement, the linear array shows an equivalent half-power beamwidth of 118°, covered by 13 beams, with the peak gain varying from 7 to 10 dBi. The gain ripple within the equivalent beamwidth is less than 0.9 dB. The output 1-dB compression point ( $P_{1\,\text {dB}}$ ) is measured as 29.5 dBm, and the dc power consumption is very low (microwatts) in all switching states.

A fully integrated scalable W-band phased-array module with integrated antennas, self-alignment and self-test

Abstract: Advanced SiGe BiCMOS and CMOS processes continue to push the frontier on millimeter-wave (mm-wave) and highly integrated phased-array systems for a variety of communication applications [1,3]. Furthermore, next-generation mobile technology (5G) demands ultra-low latency and high data-rates with ubiquitous deployment supporting multi-users through the use of pico-cells. These cells may require up to hundreds of active elements capable of producing thousands of beam patterns. In order to make wide adoption of such mm-wave systems a reality, the overall cost of the system must be significantly reduced. This can be accomplished through several means. First, producing highly-integrated phased arrays eliminates the need for additional external components (such as expensive mm-wave synthesizers, amplifiers and switches), which reduces the overall system costs. Second, eliminating exotic packaging processes and materials would allow low-cost traditional manufacturing techniques to be applied to mm-wave systems. Lastly, incorporating self-test, fault-detection, health-monitoring and self-calibration into the RFIC significantly reduces the costs of factory testing (by eliminating the need for any mm-wave verifications) and enables remote-maintenance and system-reconfiguration in case of failures.