How to Design and Test a Phased Array Antenna

Modern radar and communication systems rely on phased array antennas to provide essential capabilities such as beamforming and beam steering.

Beamforming offers numerous advantages for wireless communication links, including:

• reduced interference
• increased range
• expanded number of services
• improved security

This comprehensive guide offers a holistic overview of phased array antenna technology and the development workflow. Discover the fundamental principles behind phased array antenna design and test, including measurement techniques and calibration. Gain insights into cutting-edge simulation tools, practical design considerations, and test methodologies.

What is a phased array antenna?
An antenna array requires multiple individual antennas, called elements, to work together as a unit. Designers configure this collection of antenna elements in such a way that the radiation pattern of each element combines with neighboring antennas to form an effective radiation pattern called the main lobe.

The antenna array design maximizes the energy radiated in the main lobe while reducing the energy radiated in the sidelobes by leveraging the constructive and destructive interference of the signals in a process called beamforming. The phased array antenna (PAA) performs beam steering through algorithms manipulating the independent phase and amplitude fed into each antenna element.

This ebook covers phased array antenna fundamentals, along with the evolution of phased array technology, including transceiver architectures and beamforming methodologies.

How phased array antennas work
Modern PAAs beam steer electronically, so engineers commonly refer to phased arrays as electronically scanned arrays (ESAs). However, the original antenna arrays that dominated classical radar systems scanned mechanically. A rotor steered the radiating element, and a gigantic antenna received signals. This approach resulted in a bulky, slow maneuvering system prone to single-point failures. Since evolving to ESA technology, phased array antennas continue to improve overall reliability in a smaller footprint.

The two types of electronically scanned phased arrays are:

• passive electronically scanned phased arrays (PESA)
• active electronically scanned phased array (AESA)

Engineers use multiple approaches to phase shift individual elements. However, the simplest method is to use delay lines that can turn on and off between the elements and the source or receiver.

The phased array antenna enables almost instantaneous beam steering by electronically controlling element amplitude and phase adjustments. This feature allows for faster and more flexible searching.

Instantaneous beam steering makes phased arrays ideal for modern communication system applications because, like radar systems that track multiple targets, multiple beams enable simultaneous communication with handsets, ground stations, or satellites.

What are the disadvantages of a phased array?
Phased array antennas deliver significant advantages, including beam steering, flexibility, and element redundancy. However, engineers looking to implement PAAs must consider key tradeoffs—particularly technical complexity and cost.

Phased array antenna systems depend on precise control over the phase and amplitude of the signal at each antenna element. This complexity requires sophisticated hardware and software to manage the array's operations, which in turn, makes design, implementation, and maintenance far more challenging and time-intensive when compared to simpler antenna systems.

In addition to the design and development complexity, integrating numerous components, such as phase shifters, amplifiers, and control systems, contribute to the high cost of phased array antennas.

Despite these disadvantages, the benefits of phased array antennas outweigh the drawbacks in many advanced applications.

What is the difference between phased array and linear array antenna?

Phased array and linear array antennas are both types of antenna arrays, which consist of multiple antennas operating together to transmit or receive signals. However, a linear antenna array consists of elements arranged in a straight-line (linear) configuration.

Linear array antennas, as opposed to phased array antennas, provide simpler, cost-effective solutions for applications able to tolerate fixed beams. While a phased array antenna electronically beam steers, the physical arrangement of the antenna elements determines the beam direction of a linear array. To change the beam direction, the entire antenna array must move.

What are the applications of phased array antenna?

For decades, radar was the primary application space for phased array antenna topologies. However, trends in component technologies like multiple transmit/receive (T/R) modules per chip and GaN power amplifiers (PA) continue to reduce the size and cost of phased array antenna.

The expanding market application potential paves the way for commercial communications and radar systems in automotive, health care, 5G, and SATCOM industries. In 5G applications, the successful implementation of massive machine type communication (mMTC) and the extreme data throughput specified in the International Mobile Telecommunications-2020 (IMT2020 Standard) depend on phased array technology. Similarly, agile scanning phased arrays provide the rapid tracking and continuous connection necessary for increasingly common low Earth orbit (LEO) satellites in the New Space arena and satellite communications.

After discussing phased array technology, theory of operation, and applications, the eBook delves into the phased array antenna design and development workflow. Using Keysight phased array antenna workflow solutions; this document details phased array antenna design principles, circuit, and system design considerations, over-the-air (OTA) test basics, and field servicing.

Engineers must optimize design and test cycle time to meet high-volume production demands in expanding commercial markets. However, the extreme complexity and increasing system integration of phased array systems present many testing challenges. Read this eBook to determine the best measurement methodology and instruments for your phased array antenna design, calibration, and test needs.