C and X-Band LSA Transmitter Source.
Abstract
Layers of uniform GaAs were epitaxially grown, from a Ga-solution, with thicknesses up to 250 micrometers and electron concentration from 1.0 to 2.0 x 10 to the 15th power/cu cm. Peak to valley current ratios up to 2.25:1 were measured. Circuit parameters including optimum load resistance were studied and results are presented. An improvement in oscillator efficiency by a factor of 1.5 resulted from resonating the second harmonic in some devices. Two types of microwave resonators were used and both incorporated 1/4 wavelength transformers with inherent preferential loading of the fundamental frequency. Mechanical and electronic tuning were also studied. The degradation of efficiency when increased average power was dissipated was measured and explained. Pulse modulators were also investigated. The SCR switched lumped line type modulator appeared best for use with very high power LSA sources. Sample pulsers were able to deliver over 550 volts into a 50 ohm load. The lumped line (PFN) could be optimized to provide a good sin x/x type spectrum. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1971
- Accession Number
- AD0733425
Entities
People
- David W. Woodard
- Joseph S. Bravman
- Lester F. Eastman