Two-dimensional modulation and instability of a short wave riding on a finite-amplitude long wave
Abstract We study the effects of a long wave of finite amplitude on a short wave propagating in a different direction. To facilitate analytical treatment, the long wave is modelled by Gerstner's exact solution, and Lagrangian coordinates are used. Focus is first on the moderately long-scale modulation within a duration comparable to the period of the long wave. The angle of inclination is allowed to be arbitrary. Extension to the evolution over much longer time and distance of propagation is then made for a short wave colinear with the long wave but modulated slowly in both longitudinal and transverse directions. The instability of the short wave due to oblique side bands is examined, and is found to be significantly enhanced by the presence of the long wave.
This paper presents design and characteristics of a compact, highly integrated Ka-band T/R module built by using a miniature magnetron in the transmitter chain. By implementing a solid-state modulator and microstrip design in the microwave part of the receiver, the overall size of the module has been reduced significantly. The module provides capabilities to realize Doppler date processing by using a digital coherent-on-receiver technique.