It sounds really scary but it really isn't. Actually- it is a natural evolution in the technology.

Once upon a time there was RADAR and it was good. It was very, very good and gave the ALlies a major advantage in the second world war. The technology was proven and all the world powers wanted to use it for civilian and military purposes.

It works like this:

Every RADAR dish is a dual mode device: it sends out a signal and it listens for its return. Ignore the math- it's really that simple.

Old Radar dishes look a lot like this: A single transmitter and a receiver, or if you are into tech-speak- a transceiver.

Most RADAR acts in half-duplex as it sends a pulse and then "listens" for a return. The transitions in send-receive cycle are quite fast as we're talking about light speed wave.

Big changes in RADAR technology took place over the course of the Cold War.

One of the biggest one were breakthroughs in signal processing. Ironically this came from the Navy and their quest to make their Sonar hear better.

A Signal Processor is usually a chip with firmware that can read and process a raw signal feed. This is great when you've got complex analog data and want to quickly change it into a form that is much more useful. These devices are smart so their software can be changed. They can do really neat stuff like filter out noise and process the return signal. You see it every time you watch the weather- that is how (among other things) Doppler radar works.

SO... if we have this antenna with one transmit and receive element, wouldn't it provide better, sharper radar performance if we used MORE than one transceiver element? It is idea that phased array radar is based on.

In the 70s the US Navy needed a new, powerful radar system to protect their carriers. The whole ship was designed around the Ticonderoga class missile cruisers were built around a huge phased array radar.

The AEGIS system is built around the SPY phased array radar. Note the bulky conning tower- the whole this is a phased array.receiver.

A different part of the system- this gives you a better look at a phased array- each square is an individual transceiver.

This makes the area of the radar "receiver/transmitter" exponentially more powerful and sensitive.

Look for this technology to be coming to your weather Radar soon.

In the next decade the weather radar systems will be gradually replaced by a phased array pulse doppler system currently under development by a consortium of Universities and Industry. The new weather images will be so detailed that meteorologists can watch a tornado form and watch it develop in increments of fractions of a second until it dissipates. It's like an MRI machine for weather- they'll be able to see it from the inside.

The phased array concept also works for simple receivers. In fact when NASA designed the New Horizons probe to fly by Pluto they needed an antenna that was powerful and sensitive enough to send and receive data over one of the longest communications loop in history.

New Horizons flew with a phased array communications antenna and it performed flawlessly.