Sensors Guide · Air Combat
Radar Systems
How fighters see the invisible — from magnetrons to AESA arrays
Twelve fighter radars compared, five generations of technology explained, and the never-ending duel between radar and stealth.
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
Simple pulse radar. Could detect aircraft but limited range and resolution. Used in the F-86 and MiG-15.
Pulse-Doppler
Filtered ground clutter using Doppler shift — look-down/shoot-down capability. AWG-9 (F-14), APQ-120 (F-4).
Mechanically Scanned
Flat-plate antenna steered mechanically. Better resolution. APG-70 (F-15E), N011 (Su-27).
PESA
Passive Electronically Scanned Array — beam steered electronically from one transmitter. Irbis-E (Su-35), 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 to scan the sky. Simple, reliable, and proven — but slow to scan and can only do one thing at a time (search OR track, not both simultaneously).
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 |
| N035 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 — scan the entire sky in milliseconds
Multi-function — simultaneously search, track, jam, and map terrain
Low Probability of Intercept (LPI) — spread signals across frequencies, hard to detect
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 | First operational AESA fighter radar |
| AN/APG-81 | F-35 | ~1,200 | 150+ km | Most advanced 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 | Estimated RCS | Equivalent To |
|---|---|---|
| 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 (despite a 52 m wingspan!) |
Counter-Stealth Technologies
No aircraft is truly invisible. Several technologies can detect stealth aircraft:
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
Detect aircraft by heat signature, no emissions needed. Su-35 (OLS-35), Rafale (OSF), Typhoon (PIRATE), F-35 (DAS).
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
The first operational AESA radar on a fighter. The APG-77 gives the F-22 first-look, first-shot, first-kill capability — detecting a 1 m² target at 250+ km while staying virtually undetectable itself thanks to LPI techniques. It can even function as a narrowband jammer.
Irbis-E — The Passive Powerhouse
The most powerful fighter PESA ever built. With 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‘s integrated suite, it automatically fuses radar, IRST, EW and off-board data into one unified picture. It simultaneously tracks 20+ targets, maps terrain with SAR, performs electronic attack, and shares everything via Link 16.
Fighter Radar Comparison
Twelve radars that equip the world’s front-line fighters
| 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 |
| PS-05/A Mk4 | AESA | Gripen E | 150+ km | 20+ | 🇸🇪 Sweden |
| Type 1475 (KLJ-7A) | AESA | J-20 | 200+ km | 20+ | 🇨🇳 China |
| EL/M-2052 | AESA | Tejas Mk2 | 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.