Phased array

About: Phased array is a research topic. Over the lifetime, 19428 publications have been published within this topic receiving 229231 citations. The topic is also known as: Phased Array Radar, PAR.

Selective modification of antenna directivity pattern to adaptively cancel co-channel interference in TDMA cellular communication system

Abstract: A base station signal processing mechanism for a time division multiple access (TDMA) cellular communication system adaptively controls weighting coefficients of the base station's phased array antenna in a manner that forms a directivity pattern whose gain and/or nulls maximize the signal to noise ratio in the presence of co-channel users whose communication time slots overlap a communication time slot of a desired user. The signal processing mechanism performs correlation processing of synchronization patterns contained in signals transmitted by co-channel users to identify times of transitions between successive co-channel users' communication time slots relative to a time of transition of the desired user's communication time slot, and deriving weighting coefficients in accordance with the times of transitions.

An Eight-Element 2–16-GHz Programmable Phased Array Receiver With One, Two, or Four Simultaneous Beams in SiGe BiCMOS

Abstract: This paper presents an eight-element 2–16-GHz programmable phased array (PPA) receiver in a 0.13- $\mu \text{m}$ SiGe BiCMOS with the reconfigurable number of beams and with the digital beamforming (DBF) capabilities. The eight-element chip can be configured for one, two, or four simultaneous beams or as an element-level DBF receiver. This is achieved using reconfigurable input switching and output combining networks with wideband active switches and combiners. The phased array channel results in a 5-b performance at 3–14 GHz (rms error $P_{\text {1 dB}}$ of −20 dBm per channel when all channels are activated. The chip consumes 250 mW per channel, which is competitive knowing its bandwidth and linearity. The DBF function also results in a wideband response with a gain and an NF of 15–16 and 12–13 dB, respectively, and high linearity (input $P_{\text {1 dB}} = -16$ dBm) at 2–16 GHz. The programmable phased array receiver allows a single chip to be used over $S$ -, $C$ -, $X$ -, and $Ku$ -bands for a variety of applications such as satellite communications and point-to-point links. This results in faster and lower-cost phased array development since the same chip and its field-programmable gate array control can be reused from system to system, but with different antenna and grid spacing. The PPA removes the need to develop a different chip for every application and allows the development of phased arrays at commercial scales.

Joint Target Assignment and Resource Optimization Framework for Multitarget Tracking in Phased Array Radar Network

Abstract: In this article, a joint target assignment and resource optimization (JTARO) strategy is proposed for the application of multitarget tracking in phased array radar network system. The key mechanism of our proposed JTARO strategy is to employ the optimization technique to jointly optimize the target-to-radar assignment, revisit time control, bandwidth, and dwell time allocation subject to several resource constraints, while achieving better tracking accuracies of multiple targets and low probability of intercept (LPI) performance of phased array radar network. The analytical expression for Bayesian Cramer–Rao lower bound with the aforementioned adaptable parameters is calculated and subsequently adopted as the performance metric for multitarget tracking. After problem partition and reformulation, an efficient three-stage solution methodology is developed to resolve the underlying mixed-integer, nonlinear, and nonconvex optimization problem. To be specific, in Step 1, the revisit time for each target is determined. In Step 2, we implement the joint signal bandwidth and dwell time allocation for fixed target-to-radar assignments, which combine the cyclic minimization algorithm and interior point method. In Step 3, the optimal target-to-radar assignments are obtained, which results in the minimization of both the tracking accuracy for multiple targets and the total dwell time consumption of the network system. Simulation results are provided to demonstrate the advantages of the presented JTARO strategy, in terms of the achievable multitarget tracking accuracy and LPI performance of phased array radar network.

Spacecraft antennas and beam steering methods for satellite communciation system

Abstract: An advanced active element phased array satellite antenna is disclosed. Incorporating these novel antenna systems on a constellation of low Earth orbit spacecraft, allows phone customers worldwide to communicate through a system whose switching intelligence resides on orbit, bypassing traditional land-based networks, and offering a revolutionary expansion of communications potential. The present invention utilizes electronic beam steering is utilized to provide extremely high gain signals. In one preferred embodiment, a satellite (S) includes an Earth-facing array (10) of hexagonal antenna facets (12), mated together along their sides to form a slightly flattened, hemispherical shell. The antenna array (10) is connected to two rectilinear, unfurled, solar panels (P). The antennas (10) transmit and receive signals from terrestrial units located within the footprints (14) of the beams (11). Another embodiment (34) uses deployable, folding panels (41) which maximize panel surface area for a given weight and launch vehicle container volume. The panels (41) are stacked upon a central plate (39) along the depth axis of the container in accordion fold layers and are separately deployed radially from the center (C) of the central plate (39). The contour of the deployed panels permit the antenna beam footprints (14) to cover the desired area.

Low Probability of Intercept Antenna Array Beamforming

Abstract: A novel transmit array beamforming approach is introduced that offers low probability of intercept (LPI) for surveillance radar systems employing phased array antennas. Radar systems are often highly visible to intercept receivers due to the inherent two-way versus one-way propagation loss. In this paper, the traditional high-gain antenna beam scanned across a search region is replaced with a series of low-gain, spoiled beams. Keeping the transmit antenna gain low reduces the radar visibility, but the radar's antenna performance remains unchanged as the original high-gain beam can be formed by processing the set of spoiled beams. Large transient power density radiated in a traditional scan is replaced with low power density persistently radiated at the target throughout the scan time. The detection performance of the radar is not affected since the total energy on the target is the same. Derivation of the complex weights to synthesize the high-gain patterns from the low-gain basis patterns is presented for both one-way and two-way beam patterns.