Then how could fighters ever fly in front of each other or in formation, if radars were on?
I may be doing the author a disservice and mis-remembering, it might have just being cooked by the radar energy that killed the pilot rather than radiation poisoning.
I think it was Firebreak by Richard Herman Jnr.
The pilot is encased in a metal aircraft which to some degree acts as a Faraday cage, shielding him from RF energy, especially if illuminated by radar from the rear. When military planes are flying in close formation they generally all aren’t using radar. The Mig-25 was a special case of an extremely powerful radar designed to “burn through” jamming by the bomber fleet it would attack.
When activated the aircraft radar beam is quite narrow and usually scanning over a fairly broad volume. By contrast if the radar was powered up on the ground in a static heading, and if a poor unsuspecting person or animal happened to walk into the tightly focused microwave beam, it might not be pleasant.
If the fighter is on the tail of a hostile opponent in combat, his radar could be locked on, meaning (for older radars) it’s no longer scanning but dwelling on the hostile target. In that case radar energy and potential long term health problems are the least of the opponent’s worries.
Which appears to be the winner. From Global Security’s blurb on it, the radar can image a basketball in geosynchronous orbit and is the only phased-array radar to able to do so.
For a given value of “radar” I guess we can include things like Arecibo. (From the wiki, 20 TW, with a “T” continuous isotropic radiated power at 2380 MHz.) Which is useful I guess when you image asteroids like 4769 Castalia. (1.4 km radius, no idea how far it was away when they imaged it, as it can be a NEO on occasion.) 4769 Castalia - Wikipedia
I don’t think the Arecibo dish ever transmitted 20 TW actual power. The actual transmitter output power is about 1 megawatt, but the dish has 72 dBi gain at 2.38 Ghz, so the effective isotropic radiated power can be up to 20 TW: Ham Radio Blog by AG1LE: Visit to Arecibo Observatory
If the 72 dBi gain figure is correct, the EIRP is actually “only” 15.8 TW and the ERP is 9.6 TW, according to this gain calculator:
However ERP is still real power in terms of RF power flux density when on axis, so I wouldn’t want to be in the beam pattern of Arecibo when operating.
OTOH I think the Arecibo beam width is only 4 arc minutes, or 0.06 degrees. So it is incredibly directional.
Directionality. Super-brief, you point the radar beam away from the crew.
Less brief. Joema mentioned dBi. Standing for dB relative to an “isotropic radiator”, aka an antenna that radiates evenly in all directions of the sphere around it. For most purposes, isotropic is a bad idea - why waste power beaming your radio station away from your listeners, or why send weather radar into the ground? Fortunately, isotropic is hard/impossible. If you look up some beginner ham radio info, they have maps & tables with directional info for various simple antennas. Phased array means you combine lots of little antennas to get even better directionality. Overall, this means that the more directional the antenna, the higher power in that smaller region. Given the same radar generator, a missile tracking radar would put more power on a spot than a hemisphere general-detection radar.
I know of two negative microwave/radio/cellular/tv/radar effects. One is a military less-lethal project that is basically a antenna on a humvee - tries to heat your skin in general, supposed to make a mob feel like their skin is on fire and hopefully make mob run away. Other is on powerful ground or ship-based radar. The “do not enter this area while radar is on” area, usually directly in front of the dish. This one could be lethal, but on the bright side if you run when you start feeling warm, I’ve been told the eyes are most vulnerable so you will probably just go blind.
Given OSHA type laws, I would expect that any civilian-grade, man portable radar would be required to be too low power for that.