Technical Radar Terms

Palmer Scan: Conical scan superimposed on another type of scan pattern - usually a spiral pattern.

Parabolic Antenna: An antenna consisting of a parabolic reflector and a radiating or receiving element at or near its focus. If the reflector is in the shape of a paraboloid, it is called a paraboloidal reflector.

Parabolic Reflector: An antenna reflector in the shape of a parabola. It converts spherical wavefronts from the radiating element into plane wavefronts. The graphic shows a trailer mounted Parabolic Antenna used by the US Army during the 1950's.

Parabolic Antenna

Parallel-Connected Duplexer: Configuration in which the tr spark gap is connected across the two legs of the transmission line one-quarter wavelength from the T-junction.

Parameter: A quantity which may have various values, each fixed within the limits of a stated case or discussion. In the present case, some examples of parameters; would be: radar frequency, limited by the tuning range of the radar.

Parasitic Array. An antenna array containing one or more elements not connected to the transmission line. An antenna with a driven element and one or more parasitic elements.

Parasitic Array: An antenna array containing one or more elements not connected to the transmission line. An antenna with a driven element and one or more parasitic elements. Note that Antenna Terms are located in a different dictionary section.

Parasitic Array

Parasitic Element: A directive element that is not connected to a radio transmitter or receiver either directly or via a feeder, but is coupled to the driven element only by the fields.

Passive Angle Tracking: Tracking of a target using radiation from the target (such as jamming), with no radiation from the radar itself. Only angular tracking is possible under these conditions since no measurement of time of travel of radiation to the target is possible, as is required to obtain target range.

Path: In communications systems and network topologies, a route between any two points.

Pawsel Stub: A device for connecting an unbalanced coaxial feeder to a balanced antenna.

PC: [Pulse Compression] The process used in search and tracking pulse radars whereby the transmitted pulse is long, so as to obtain high average transmitter output power, and the reflected pulse is processed in the radar receiver to compress it to a fraction of the duration of the transmitted pulse to obtain high definition and signal strength enhancement. Pulse compression may be accomplished by sweeping the transmitted frequency (carrier) during the pulse. The returned signal is then passed through a frequency-dependent delay line. The leading edge of the pulse is therefore delayed so that the trailing edge catches up to the leading edge to produce effectively a shorter received pulse than that transmitted. Pulse compression radars are also referred to as CHIRP radars.

Peak Envelope Power: The average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle at the crest of the modulation envelope taken under normal operating conditions.

Peak Power: Maximum power of the rf pulse from a radar transmitter.