Sensors Guide · Air Combat
Radar Systems
How fighters see the invisible — from magnetrons to AESA arrays
Twelve fighter radars compared, five stages of technology explained, and the relationship between radar and stealth. Published performance figures are estimates or manufacturer claims with different test conditions, not a controlled ranking.
What Is Radar?
Radio Detection And Ranging — the eyes of every modern fighter
RADAR = RAdio Detection And Ranging. A radar system sends out radio waves and listens for echoes bouncing off objects. By measuring the time delay and frequency shift, it can determine an object’s range, speed, altitude, and direction.
In fighter aircraft, radar is the primary sensor for detecting, tracking, and engaging targets — especially at night, in clouds, or beyond visual range. Modern fighter radars can simultaneously track 20+ targets, guide multiple missiles, map terrain, and even jam enemy electronics.
Evolution of Fighter Radar
Eighty years from simple pulse radar to electronically steered arrays
Magnetron
Early pulse radars had limited range and resolution; interceptor variants such as the F-86D carried such systems. Basic ranging equipment on a standard MiG-15 should not be conflated with a full search radar.
Pulse-Doppler
Doppler processing helps separate targets from ground clutter and enables look-down/shoot-down capability. Examples include AWG-9 (F-14) and APG-63 (F-15); APQ-120 should not be presented as a pulse-Doppler example.
Mechanically Scanned
Mechanically steered flat-plate and other antennas continued to improve. Examples include APG-70 (F-15E); N011 was associated with early Su-27M development, not every Su-27 variant.
PESA
Passive Electronically Scanned Array: central transmission with electronic phase control. MiG-31 Zaslon entered service in the 1980s; later examples include Irbis-E (Su-35) and Bars (Su-30MKI).
AESA
Every element is its own transmitter/receiver. Near-instant steering, LPI, jam-resistant. APG-77 (F-22), APG-81 (F-35).
Radar Types Explained
Three architectures — from rotating dishes to solid-state arrays
Mechanically Scanned Array (MSA)
The antenna physically rotates or tilts. Mechanical motion limits scanning speed, but suitable processing can interleave search and tracking, including track-while-scan (TWS). It is incorrect to say mechanical radars must choose only search or only track.
Pros: Cheap, reliable, field-repairable
Cons: Slow scan rate, limited multitasking, easy to detect
Passive Electronically Scanned Array (PESA)
Uses a single transmitter feeding many antenna elements through phase shifters. The beam is steered electronically — much faster than mechanical scanning. However, it still has a single point of failure (the transmitter).
Pros: Fast beam steering, good power output, reliable
Cons: Single transmitter = single point of failure, limited frequency agility
| Radar | Aircraft | Detection Range | Tracks |
|---|---|---|---|
| Irbis-E | Su-35 | 350–400 km (3 m² target) | 30 air + 4 ground |
| N011M Bars | Su-30MKI | 200 km | 15 tracks, 4 engage |
| Zaslon-M | MiG-31BM | 300 km | 24 tracks, 6 engage |
Active Electronically Scanned Array (AESA)
The gold standard of modern fighter radar. Each of the 1,000–2,000 antenna elements (T/R modules) is its own tiny radar. This enables:
Near-instant beam steering — redirect the beam rapidly; full-volume search still requires dwell time and depends on range and coverage.
Multi-function — simultaneously search, track, jam, and map terrain
Low Probability of Intercept (LPI) — waveform, power and frequency management reduce the chance of interception; they do not make the radar undetectable.
Electronic attack — focus energy to jam enemy radars
Graceful degradation — if some elements fail, the radar still works
Frequency agility — change frequency thousands of times per second
| Radar | Aircraft | T/R Modules | Range | Key Feature |
|---|---|---|---|---|
| AN/APG-77 | F-22 Raptor | ~2,000 | 250+ km | An early representative operational AESA fighter radar |
| AN/APG-81 | F-35 | ~1,200 | 150+ km | Supports F-35 system-level sensor fusion |
| AN/APG-82(V)1 | F-15EX | ~1,100 | 200+ km | AMRAAM + JASSM fire control |
| AN/APG-83 SABR | F-16V | ~1,000 | 150+ km | AESA retrofit for legacy F-16s |
| RBE2-AA | Rafale | ~1,000 | 200+ km | First European AESA fighter radar |
| Captor-E | Typhoon | ~1,400 | 200+ km | Repositionable array (wider scan) |
| KLJ-7A | JF-17 Block 3 | ~1,000 | 170+ km | Chinese export AESA |
Stealth vs. Radar
The eternal battle between hiding and finding
How Stealth Works Against Radar
Stealth aircraft use several techniques to reduce their Radar Cross Section (RCS):
Shape
Angled surfaces reflect radar energy away from the receiver — the F-117’s facets, the F-22/F-35’s blended curves.
Radar-Absorbing Materials
Special coatings and structural materials that absorb radar energy and convert it to heat.
Internal Weapons Bays
External weapons create huge radar returns. The F-22, F-35, J-20 and Su-57 all carry weapons internally.
Edge Alignment
All edges point in the same few directions, creating narrow radar “spikes” instead of reflections everywhere.
| Aircraft | Unverified estimates cited in the original article | Illustrative area analogy only |
|---|---|---|
| B-52 (non-stealth) | 100 m² | Small building |
| Su-27 Flanker | 10–15 m² | Large car |
| F-16 | 1–5 m² | Desk |
| Eurofighter Typhoon | 0.5–1 m² | Chair |
| F/A-18E Super Hornet | ~1 m² | Chair |
| Rafale | ~0.5 m² | Suitcase |
| Su-57 Felon | ~0.1–0.5 m² | Football |
| F-35 Lightning II | ~0.005 m² | Golf ball |
| F-22 Raptor | ~0.0001 m² | Marble |
| B-2 Spirit | ~0.0001 m² | Marble (original analogy, despite a 52 m wingspan); table-wide caveat: these circulating RCS estimates are not verified here. RCS varies with frequency, aspect, polarization and configuration; do not use this table as a stealth ranking. |
Counter-Stealth Technologies
Stealth does not mean invisibility. These methods may provide detections under some conditions; detecting a signal, maintaining a track and obtaining weapon-quality guidance data are different thresholds.
Low-Frequency Radar
Stealth shaping is optimized against X-band. VHF/UHF waves with wavelengths similar to the aircraft’s features can still detect it — e.g. Russia’s Nebo-M.
Passive Detection
Instead of emitting, listen for the stealth aircraft’s own emissions — radio, datalink, radar. Czech Vera-NG, Chinese DWL-002.
Infrared Search & Track
Passive infrared sensing can complement radar. Examples include Su-35 OLS-35, Rafale OSF and Typhoon PIRATE. F-35 DAS is a distributed infrared system with wider situational-awareness roles, not an identical standalone IRST.
Bistatic / Multistatic Radar
Transmitter and receiver in different locations — stealth shapes can’t deflect energy away from every receiver at once.
Famous Fighter Radars
Four systems that defined their eras
AN/AWG-9 — The F-14 Tomcat’s Eyes
The legendary radar that made the F-14 Tomcat the fleet’s guardian. Could track 24 targets simultaneously and guide 6 AIM-54 Phoenix missiles at once — unprecedented in the 1970s. Detection range exceeded 300 km for bomber-sized targets.
AN/APG-77 — The AESA Pioneer
An early representative operational AESA fighter radar, rather than the first worldwide. APG-77 supports the F-22 first-look, first-shot, first-kill design objective. This page does not substantiate its original 1 m²-at-250+ km figure; LPI reduces interception probability rather than guaranteeing invisibility. Public descriptions also discuss some narrowband jammer.
Irbis-E — The Passive Powerhouse
A high-power fighter PESA example. Public descriptions cite 20 kilowatts of peak power, the Su-35‘s radar can detect a 3 m² target at an astounding 350–400 km. A unique hydraulic-mechanical mount extends its electronic scan to ±120°.
AN/APG-81 — The Sensor Brain
The APG-81 doesn’t just see — it thinks. Part of the F-35 integrated sensor suite. System-level fusion combines radar, infrared, electronic-warfare and off-board data; it is not performed by the radar alone. Modes include tracking, SAR mapping and some electronic-attack functions. Data exchange involves Link 16, MADL, compatibility and information limits, not sharing everything over Link 16.
Fighter Radar Comparison
Twelve radar examples. Public range and track figures use different assumptions and modes and cannot establish a performance ranking.
| Radar | Type | Aircraft | Range | Tracks | Country |
|---|---|---|---|---|---|
| APG-77 | AESA | F-22 | 250+ km | 20+ | 🇺🇸 USA |
| APG-81 | AESA | F-35 | 150+ km | 20+ | 🇺🇸 USA |
| APG-82 | AESA | F-15EX | 200+ km | 20+ | 🇺🇸 USA |
| APG-83 SABR | AESA | F-16V | 150+ km | 20+ | 🇺🇸 USA |
| Irbis-E | PESA | Su-35 | 350–400 km | 30 | 🇷🇺 Russia |
| N036 Byelka | AESA | Su-57 | 250+ km | 30+ | 🇷🇺 Russia |
| Zaslon-M | PESA | MiG-31BM | 300 km | 24 | 🇷🇺 Russia |
| RBE2-AA | AESA | Rafale | 200+ km | 40 | 🇫🇷 France |
| Captor-E | AESA | Typhoon | 200+ km | 20+ | 🇪🇺 Europe |
| Raven ES-05 | AESA | Gripen E | No comparable verified figure listed | Mode dependent | UK/Italian supplier; Swedish platform |
| KLJ-7A | AESA | JF-17 Block 3 | Public estimate 170+ km; conditions not standardized | Mode dependent | 🇨🇳 China |
| EL/M-2052 | AESA | Multi-platform integration; Tejas Mk2 fit not confirmed here | 150+ km | 64 | 🇮🇱 Israel |
Video Library
Understand the technology behind modern fighter radar
F-35 AESA Radar — The Key to Stealth Dominance
The AN/APG-81 is one of the most advanced AESA radars ever built. Why the F-35’s radar is considered its most important advantage.
How Radar Works — Electronic Warfare Fundamentals
A comprehensive introduction to radar principles, from basic pulse-Doppler to modern electronic warfare concepts.
How Phased Array Radar Works
Phased array technology is the foundation of modern military radar. How electronically steered beams give fighters a decisive edge.
IRST — The Stealth Buster
Infrared Search and Track systems can detect stealth aircraft that evade radar. How this passive sensor works and why it’s becoming essential.
Complete The Picture
Radar finds the target — missiles finish the job, and stealth tries to break the chain. Explore the other two sides of modern air combat.