  The wavelength and the propagation length of the edge magnetoplasmons,
running along the edge of a two-dimensional electron layer in a semiconductor
quantum-well structure are theoretically studied as a function of frequency,
magnetic field, electron density, mobility, and geometry of the structure. The
results are intended to be used for analysis and optimization of operation of
recently invented quantum-well microwave spectrometers operating at
liquid-nitrogen temperatures (I. V. Kukushkin {\em et al}, Appl. Phys. Lett.
{\bf 86}, 044101 (2005)).
