ELECTROMAGNETIC GENERATION TECHNIQUES.
Abstract
Coherent microwave radiation at frequencies from 6.5 to 44 GHz is generated by p-type indium antimonide at 77K with an injected electron current transverse to a magnetic field. With a waveguide or stripline coupling system, the maximum output power is about 10 microwatts for input power levels of one to five watts. Grooves of specified widths cut into the Suhl surface of the rod-shaped InSb samples generate the coherence and determine the approximate output frequency. Wavelength measurements of a surface wave on the rod show that the effective groove width is about equal to a half-wavelength. A theory of double-stream interaction in a thin plasma layer with a magnetic field transverse to the current flow is formulated and predicts instabilities in the observed frequency range. Correct quantitative predictions made by the theory are: (1) the hole density required for onset of emission, (2) the minimum magnetic field which is required for emission onset at high current injection and (3) the phase velocity of the surface wave at high magnetic fields. Computer solutions of the dispersion relationship for the plasma wave instability are in good qualitative agreement with measurements of the emission frequency as a function of magnetic field and injection current. The theoretical analysis and concurrent experimental evidence demonstrates the existence of the instability in a thin-layer plasma in the absence of a magnetic field. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1968
- Accession Number
- AD0826387
Entities
People
- B. B. Robinson
- G. A. Swartz
Organizations
- Sarnoff Corporation