What antennas are used in radar?
Radar antennas form narrow, high-gain beams that set detection range (through the G² term of the radar equation) and angular resolution. Classic forms are shaped reflectors, slotted waveguide arrays and planar arrays; modern radars increasingly use active electronically scanned phased arrays (AESA) for agile, multifunction beams.[1][2]
How does the antenna enter the radar equation?
For a monostatic radar, Pr = PtG²λ²σ/((4π)³R⁴), so maximum range scales as G1/2 for fixed other parameters, and receiving aperture determines collected power.[1] Beamwidth sets angular resolution and sidelobes set clutter and jamming susceptibility.
What is monopulse?
A monopulse antenna forms sum and difference beams simultaneously, e.g., with a four-horn feed or four array quadrants; the ratio of difference to sum signals gives the target’s angle off boresight from a single pulse, enabling precise tracking.[1]
Why are low sidelobes important?
Sidelobes admit ground clutter and jamming and can create false detections; radar arrays use Taylor tapers and tight error budgets to reach low sidelobe levels.[3][1]
Frequently asked questions
What is a cosecant-squared beam?
An elevation pattern shaped so received power from targets at constant altitude is nearly independent of range.
Why are AESAs replacing mechanically scanned radars?
Electronic agility, graceful degradation and multiple simultaneous beams.
Which radar bands are common?
S, C and X bands for many surveillance and weather radars; 76–81 GHz for automotive.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “Introduction to Radar Systems, 3rd ed.”. M. I. Skolnik, McGraw-Hill. 2001.
- “Phased Array Antenna Handbook, 3rd ed.”. R. J. Mailloux, Artech House. 2017.
- “Design of Line-Source Antennas for Narrow Beamwidth and Low Side Lobes”. T. T. Taylor, IRE Transactions on Antennas and Propagation, vol. 3, no. 1, pp. 16-28. January 1955.