Comparison of theoretical and experimental results for millimeter-wave GaAs IMPATT's

Theory of the mm Wave IMPATT Diode: A Review

“…Using A and Rs same as mentioned above, the power to be delivered is 2.16W at CW and 7J = 14.7%. So EM simulation results are closer to experiment and the effect becomes important above 20 GHz[14]. Further, experimental verification has been made for a Si B B PAL eta/: THEORY OF mm WAVE IMPATT…”

“…Which theory is most appropriate is not yet decided. Even though EM simulation shows better agreement with the experimental results compared to DO simulation [14], there has been agreement of conventional Impatt theory also with experiment [22]. However, from the basic physics point of view, the following points are important for mm wave Impatt diode: (i) Since the operating frequency is beyond 30 GHz, the transit time of carriers is sufficiently small and the depletion layer thickness is less than I fJITI, (ii) Internal static field is quite large which leads to: (a) quantum mechanical tunneling and (b) non-linear characteristics of ionization rates of carriers, (iii) For materials like Ill-Y compounds, the transient behaviour and velocity overshoot and undershoot dominate over steady state behaviour.…”

“…These effects were observed to be important just above 20 GHz. Simulation has also been carried out assuming carrier transport equation [14] which significantly modifies the carrier transport behaviour and gives better rf performance compared to drift diffusion model. Delayed secondary avalanche (DSA) is an important effect in mm wave Impatt [6].…”