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Keysight Technologies
Overcoming the Challenges
of Simulating Phased-Array
Radar Systems
Application Note
Introduction
Phased array is widely used in modern radar systems for rapid multi-target search and track
operations, as well as to achieve higher resolution and better detection performance. Despite
these enviable benefits, when developing phased-array radar many issues may be encountered.
For modern engineers, that often means a myriad of test challenges, not the least of which
is finding a way to improve performance while also reducing the high cost associated with
Transmit/Receive (T/R) modules with Direct Digital Synthesizers (DDSs), digital-to-analog
converters (DACs) and Analog-to-Digital Converters (ADCs). Also of concern to the engineer is
finding a way to work effectively with the entire development team--the system architect, the
RF team and the signal processing team. Additionally, calibration of the T/R module can be dif-
ficult, not to mention time consuming and expensive. Addressing these challenges demands an
appropriate method of designing and testing phased-array radar systems; one that streamlines
the R&D lifecycle so that faster, cheaper, better phased-array radar systems can be achieved.
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Phased-array radar design:
The basics
There are two types of phased-array radar systems: passive and active The same cannot be said of radar based on an Active Electronically
(Figure 1). In a passive system, a baseband source is connected to a Scanned Array (AESA). In contrast to a PESA radar, AESA devices
single large Transmitter (Tx) with a High Power Amplifier (HPA). The Tx have T/R modules containing small Tx and Rx designs located behind
is connected to a beamformer followed by the antenna unit, the return each radiating element and the baseband source is connected to the
signals of which are connected to a single Receiver (Rx) and subse- beamformer. Transmitter power is distributed through many small
quently, to the baseband receiver. In passive systems, the signal loss PAs to the antennas, while the baseband receiver receives signals
between radiating elements and the T/R can be quite large. However, through antennas in many small Low Noise Amplifiers (LNAs). In an
because passive antenna systems have a central Radio Frequency (RF) active system, the signal loss between the PA/LNA and the radiating
source, developing a radar system based on a Passive Electronically element is much smaller than in a passive system. Electronic scan-
Scanned Array (PESA) is a fairly straightforward process. ning is therefore used, which enables faster, more flexible searching.
However, because each module contains its own RF source, develop-
ment of AESA radars is substantially more complex.
Figure 1. Two types of phased-array radar, passive-array and active-array antenna systems, are shown here.
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The platform solution
Dealing with the complexity of AESA radar development, while also The platform solution also offers trade-off analysis, T/R module and
addressing the traditional problems and challenges associated with antenna unit failure analysis, and adaptive algorithm creation support.
developing a phased-array radar requires a platform solution that And, it features links to test equipment (e.g., a signal generator,
enables effective design and test at all stages of the development arbitrary waveform generator (AWG) and signal analyzer) for hardware
process (Figure 2). The ideal platform solution relies on simulation as testing, along with support for integrated test. The links allow data to
its foundation and features a number of key characteristics, including be downloaded to an AWG for testing RF signals, and for hardware
cross-domain simulation with RF and Electromagnetic (EM), as well signals to be acquired and sent back to simulation for post analysis.
as the ability to measure both 3D and 2D antenna patterns. The A prime example of this platform solution is SystemVue.
measured antenna patterns, coupled with Tx measurements (e.g.,
waveform, spectrum and time-side-lobes) and Rx measurements (e.g.,
detection rate and false alarm rate) can be used for performance
validation.
Benefits from AESA
prototyping platform