IMPATT diode


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IMPATT diode

[′im‚pat ‚dī‚ōd]
(electronics)
A pn junction diode that has a depletion region adjacent to the junction, through which electrons and holes can drift, and is biased beyond the avalanche breakdown voltage. Derived from impact avalanche and transit time diode.
References in periodicals archive ?
Since the RF performance of IMPATT diode is strongly dependent on the carrier ionization rates of the base material, the same must be significantly influenced by the crystal orientation of the substrate (here GaAs).
Currently, the silicon IMPATT diode is the most powerful solidstate source at W-band frequencies and is being used in several developmental high performance mm-wave systems, such as missile seekers, precision guided weapons and tracking radars.(1) When operated with short bias current pulses of 50 to 100 ns and low duty cycle (< 1 percent), IMPATT diodes can deliver sufficiently high peak powers.(2) The present status of peak power capability of the Si IMPATT diodes is 42 W.(3) Commercially, devices are available with up to 20 W of peak power.(4)
Early oscillators involved a Gunn or Impatt diode matched in a waveguide and frequency controlled with a hollow cavity coupled to the waveguide.|1~ In order to decrease size, dielectric resonators consisting of low loss, high permittivity ceramic disks have been used.|2~ Figure 1 shows how these resonators are commonly coupled to the oscillator's active element, usually a transistor, through a microstrip line.
The described experimental results were obtained through intensive investigation of several types of cavity configurations loaded with a proper IMPATT diode. The purpose of these investigations was to propose workable and stable IMPATT-loaded waveguide cavities at V-band to replace the existing high cost, relatively cumbersome gas discharge noise tubes.
The IMPATT diode utilizes two phenomena to generate RF power by effecting a 180 |degrees~ phase shift between the AC voltage and current waveforms, once DC power is provided to the diode and it is properly mounted in a resonant cavity or circuit.
Further integration of another Gunn or IMPATT diode would increase the active element's output power.
In 1979, he joined Hughes Aircrafts Missile Systems Group, where he worked on high power microwave and mm-wave IMPATT diode transmitters.
Also, the breakdown voltage of the diode, the current (I) and the diode's cross-sectional area (A), play an important role in determining the noise power spectrum of the IMPATT diode.[4] The two significant factors that must be considered in the design of these IMPATT sources are the noise power level and the noise power spectrum flatness over the whole frequency band.
As compared to a Si single-drift flat-profile IMPATT diode, [19] the small signal impedance level per unit drops down to 70 to 50 percent at the same current densities.
An active antenna built by integrating a modified bow-tie antenna with an IMPATT diode at a frequency of 4 GHz has been reported on previously.
IMPATT diode technology has been application driven.
Such a device originally was proposed in 1958, [7] and the structure later was fabricated for use as a high power IMPATT diode. The device was called an integrated series IMPATT structure (ISIS).