High Power Microwave Oscillator Research Articles

Relativistic resonance traveling-wave tube with tunable oscillation frequency

A high-power microwave oscillator is realized experimentally, employing a relativistic traveling-wave tube with a feedback circuit closed by tunable Bragg waveguide reflectors. A gigawatt-pulse power level is attained in the oscillator in the 3-cm wavelength range, which is maintained when the carrier frequency is tuned in a range of about 5%.

Phase locking of high power microwave oscillators with large injection power ratios

An analysis of phase locking between two high power microwave oscillators with large injection power ratios has been developed by making use of the concept of a lumped circuit, which makes it possible to predict the locked relative phases more accurately and provides a more suitable phase-locking condition for most practical cases. Sample phase calculations starting from different initial conditions are presented, which show that the conventional phase-locking theory is sufficient only when the frequency difference between the oscillators is small enough, however, it must be modified when the frequency difference and the power ratios are both large. Moreover, it has also been found that a longer locked time and a wider locking bandwidth are expected by the new results than those obtained by the conventional phase-locking theory.

Varactor diode for tuning high-power solid-state microwave oscillators

A novel varactor diode has been developed for tuning high-power microwave solid-state oscillators. The resulting output power against frequency remains much flatter than conventional high-power varactor-tuned oscillators.

Beam-Lead plated heat sink GaAs IMPATT: Part I—Performance

GaAs IMPATT devices are currently being developed for use as high-power microwave oscillators. Since low thermal impedance is required for dissipation of high input powers, this device is usually fabricated by thermal compression bonding to a diamond heat sink or a multimesa plated heat sink. This paper discusses the development of 4-mesa beam-leaded plated heat sink (BLPHS) C- and X-band GaAs IMPATT diodes. A description of the fabrication procedures is given, whereby the beam-lead interconnects are formed as part of the wafer fabrication procedure. Diodes tested at 5 GHz give up to 7.3 W of output power at 13.5- percent efficiency at a junction temperature of approximately 210°C. X-band diodes, although the data is more limited, show efficiencies up to 16.5 percent (2.2 W) for fiat profile diodes, and up to 20.8 percent for lo-hi-lo profile diodes. BLPHS diodes, therefore, are limited in their efficiency by the epitaxial material's doping profile. Accelerated stress aging data taken to date on BLPHS units show them to have an estimated mean time to failure greater than 2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> h at 200°C, which is comparable to thermal compression bonded to diamond units.