A high performance millimeter-wave front-end for automotive radar is presented. A dual cavity, varactor tuned GaAs Gunn oscillator, with 2 GHz electronic tuning range and over 12 dBm of output power at 76.5 GHz is reported. The oscillator also provides over 20 dBm of output power at 38.25 GHz at a separate port. Injection locking the oscillator using a lower power, 38 GHz signal at this port has been demonstrated. The results are compared to a less complex bias-tuned Gunn oscillator design. A single-balanced Schottky diode based mixer on microstrip is also presented with 11 dB conversion loss in the band of interest. High performance ridge waveguide based microstrip to waveguide transitions to connect the oscillator and mixer have been realised. Two back-to-back transitions exhibit a return loss of better than 22 dB and an insertion loss of 1.5 dB in the 2 GHz band of interest.
[1]
S. Hopfer,et al.
The Design of Ridged Waveguides
,
1955
.
[2]
L.P. Ligthart,et al.
The Colarado Multistatic FMCW Radar System
,
1998,
1998 28th European Microwave Conference.
[3]
R. G. Davis,et al.
Phase-locked millimeter-wave two-port second-harmonic Gunn oscillators
,
1991
.
[4]
S. B. Cohn,et al.
Optimum Design of Stepped Transmission-Line Transformers
,
1955
.
[5]
P.J.F. Swart,et al.
Collision Avoidance Radar Able to Differentiate Objects
,
1997,
1997 27th European Microwave Conference.