Phased array antennas can take many forms. Experts use topology and beamformer technology to classify different types of phased array antennas.
Phased Array Topology
One way to distinguish the types of phased array systems is to classify them by the relative position of the antenna elements. Most systems fall into one of the following topological types:
Line (1D) arrays: The antenna elements are arranged in a horizontal line to change the azimuth angle of the beam or in a vertical line to control the elevation.
Planar (2D) arrays: The antenna elements are arranged on a flat surface (a planar structure) and can be steered in both elevation and azimuth angles to cover the entire space above the antenna.
3D array: The antenna elements are arranged across a volume, allowing the steering of one or more beams in any direction.
Types of Beamformers
Passive electronically scanned array (PESA): A passive phased array is an antenna with a single transceiver for the entire array. This is the most common type of phased array configuration.
Active electronically scanned array (AESA): An active phased array is an antenna in which each antenna element or subset of elements has an analog transceiver module to produce the phase shift in each element. Military applications tend to use this more advanced approach.
Digital beamforming (DBF) phased array: A DBF array antenna uses a digital transceiver module to vary the phase and amplitude in each antenna element. It can also produce multiple beams and uses a field-programmable gate array (FPGA) chip or an array computer to digitally form the antenna pattern. Digital beamforming arrays can also develop radiation pattern nulls to reduce power sensitivity and receive sensitivity are purposely minimized to mitigate interference to or from known directions.
Hybrid beamforming phased array: The AESA and DBF approaches can be combined to form a hybrid beamforming phased array. This approach includes subarrays. Each subarray uses an analog transceiver, and each array element in the subarrays has its own digital transceiver. This approach can create clusters of simultaneous beams.
Advantages and Applications of Phased Array Antennas
Engineers designing communication systems and sensors use phased array antennas to create a spatially selective wireless RF signal source. An antenna array enables a system to take advantage of one or more of the following capabilities:
Combine multiple antenna elements to create a large aperture and a stronger signal
Use beamforming to create an electronically steerable antenna
Use adaptive, hybrid, or digital beamforming to create beams pointing in multiple directions at the same time, and to minimize interference to and from other RF systems
These capabilities deliver some significant advantages over transitional mechanically steered reflector and mast antennas:
Electronically steered beams can scan much faster or switch beam direction very quickly.
Compared to a reflector antenna with mechanical steering and a large dish, a phased array antenna usually takes up less space and weighs less. It can fit onto the surface of a vehicle or on a building.
In most cases, phased array systems also cost less for the same level of performance, especially when integrated circuits (ICs) are used for beamforming or for the antenna elements.
Reliability. Individual components within a channel may fail without compromising the basic performance of the antenna system overall. In fact, performance degrades gracefully with component failures, in contrast to single point of failure issues with mechanical antenna systems.
Point the signal in multiple directions with a single device.
Because the power for each antenna element adds up, they are more power efficient.
These advantages led early RF pioneers to develop phased array radar and radio astronomy arrays that could amplify very weak signals from distant stars. Over time, the number of phased array applications grew to include antennas for other aerospace systems as well as medical, automotive, industrial, and communication systems.
Multidirectional array antenna systems enable:
Modern 4G and 5G telecommunication networks
Future 6G telecommunication networks
The latest WiFi access points
Radar systems for autonomous automobiles
Therapeutic medical devices
How Simulation Enables Phased Array Antenna Design
Designing even small arrays for phased array antennas would be difficult without simulation, and it becomes essential for systems with thousands of antenna elements. Everything from arracy spacing to sidelobe losses is difficult to calculate by hand. Measuring radiation patterns in an anechoic chamber is also expensive and time-consuming.
An animation of a simulation showing how a phased array antenna’s maximum gain dynamically points at a ground station as it orbits the area
With simulation, engineers can not only design their arrays and the beamforming components, but they can also optimize their systems for efficiency, cost, and speed. Teams also use simulation to understand the impact of manufacturing tolerances and material variation on the design.
Engineers use simulation tools to design, verify, and optimize antenna arrays, antenna elements, and beamforming components. They can also simulate how their antennas interact with the entire system.
A comprehensive, easy-to-use, and accurate high-frequency electromagnetics finite element tool like Ansys HFSS high-frequency electromagnetic simulation software is ideal for almost every electromagnetic aspect of simulating phased array antennas. With powerful meshing, parallel solvers, and workflows specifically created for arrays, it is the gold standard for component and system-level modeling. HFSS software simulates everything from individual waveguides to signal propagation through the entire assembly, modeling the antenna long before hardware is available.
Shooting and bouncing ray technology found in applications like Ansys Perceive EM radio frequency channel and radar signature simulation software takes simulation to the next level by enabling users to model how their antennas perform across long distances and around obstacles like shelving in a warehouse or buildings in a city. Teams designing for the local installation impact of their antenna systems use the shooting and bouncing rays (SBR) feature inside HFSS software to capture the antenna's self-coupling to the tower, buildings, or vehicle it is mounted on. Engineers can also use simulation to model how their antenna design works in a network with a system-level tool like Ansys RF Channel Modeler high-fidelity wireless channel modeling software.
Once the electromagnetic characteristics are understood and optimized, design teams need to look at the thermal and structural response of the phased array system. They can use tools like Ansys Mechanical structural finite element analysis (FEA) software or Ansys Icepak electronics cooling simulation software, which can interface with their high-frequency electromagnetic solver. And if the antenna is mounted on a vehicle or aircraft, they may need to use a CFD tool such as Ansys Fluent fluid simulation software to understand and design for aerodynamic loading at speed.
（from https://www.ansys.com/）
