Weather Radar for Single Engine Aircraft

A new approach to airborne weather radar using a simple steerable phased-array antenna is presented. This antenna avoids the need for a dish of any kind and has no mechanical scanning device. It is inexpensive to manufacture, using micro-strip techniques throughout, and has an overall gain that is equal to or better than a dish of comparable size. It is electronically scanned at about 17 frames/s through a 90 deg total angle, producing a TV picture type display.

The range, using an 8 kW peak power X-band transmitter and an inexpensive receiver, is greater than 90 miles. The model with beam width about 5 deg in the horizontal plane and 10 deg in the vertical plane fits entirely inside the wing of a Piper Cherokee. A “twin engine airplane” version with an 11 in array would have a 5 deg vertical beam width and 6 dB of additional loop gain which would permit the transmitter power to be reduced to 2 kW peak power for the 90 mile range.