Collision Avoidance Radar

The basic CAR concept.


An initial CAR system design.

A proof-of-principle wideband radar system is currently under development with the eventual goal of developing a low cost collision avoidance radar system. Various components required to complete the entire system are being assembled and/or constructed in order to test and develop the radar.

A hybrid circuit for use as the impulse generator has been modeled, built and tested. The circuit generates an ~10 V pulse of width ~300 ps. Timing circuitry has been designed for use with the generator to have a pulse repetition rate of 1 MHz. A nonlinear transmission line (NLTL), designed to compress the input pulse to a width of ~25 ps, has been monolithically fabricated. The NLTL has been mounted and packaged and is currently under test. The impulse driver, timing circuitry and NLTL will eventually be packaged together into one unit which will form the radar transmitter component.

A hybrid sampling circuit has been designed, built and tested. An input pulse waveform has been successfully reconstructed utilizing the circuit with varying delay times to sample different points along the signal. A differential amplifier circuit has been designed and built in order to integrate the output signals from the sampling circuit. A monolithic nonlinear delay line (NDL) circuit which provides voltage-controlled true time delay is currently being designed. The sampling circuit, NDL and differential amplifier circuitry will eventually be packaged together to form the radar receiver component.

Extensive modeling of the pulse driver, NLTL and sampling circuitry is being performed utilizing MDS. Modeling of unbalanced, wideband antenna structures which can readily be coupled to the NLTL driver circuits is also being performed. These antenna structures will eventually be integrated with the radar transmitter/receiver circuitry in order to provide a complete, compact, wideband system.

Improvements to the system will be ongoing, with eventual goals of building more compact systems at lower costs and at higher frequencies.

Send comments to: Cheng Liang.