How do I design a radar-communication dual function system on a shared platform?
Dual Function Radar-Communication
DFRC is being actively pursued for military applications (where radar and communication must coexist on the same aircraft or ship with limited antennas and spectrum) and for future civilian systems (automotive, 6G base stations).
- Performance verification: confirm specifications against the application requirements before finalizing the design
- Environmental factors: temperature range, humidity, and vibration affect long-term reliability and parameter drift
- Cost vs. performance: evaluate whether the application demands premium components or standard commercial grades
Frequently Asked Questions
What performance tradeoffs exist?
The fundamental tradeoffs: radar beam quality vs. communication rate: directing more power toward the radar target improves sensing SINR but reduces the power available for the communication user. Waveform design: optimal radar waveforms (constant modulus, low PAPR) carry less information than optimal communication waveforms (high-order QAM). The compromise waveform is suboptimal for both but acceptable for both. Degrees of freedom: in a MIMO system with N antennas: the degrees of freedom (spatial dimensions) are split between forming the radar beam and the communication beam. More DOF for radar means fewer for communication MIMO capacity, and vice versa.
What is the SotA in DFRC?
Research demonstrations: university labs have demonstrated DFRC systems at 2.4 GHz, 5.8 GHz, and 77 GHz using SDR platforms (USRP, Xilinx RFSoC). Key results: simultaneous radar detection (range and velocity estimation) and data communication (Mbps data rates) using a single OFDM waveform. Military programs: DARPA has funded several DFRC research programs (e.g., SSPARC: Shared Spectrum Access for Radar and Communications). Raytheon, Northrop Grumman, and BAE Systems are developing multi-function RF systems that integrate radar, EW, and communication on shared phased array platforms.
How does this relate to AESA radar?
Modern military AESA (Active Electronically Scanned Array) radars already have the hardware capability for DFRC: each T/R module can generate arbitrary waveforms, enabling: simultaneous radar and communication beams from the same array. The F-35's AN/APG-81 AESA radar has an integrated communication capability (this is often called MADL: Multifunction Advanced Data Link). The Raytheon RACR (Radar for Advanced Combat Relevance) and Northrop Grumman SABR are multifunction AESA systems. In practice: the AESA is used for radar during most of the time, with brief periods allocated to communication transmissions (time-division) rather than true simultaneous DFRC, due to the processing and waveform design challenges.