Gary H. Glover

TEMPERATURE DEPENDENCE OF THE MICROWAVE DIELECTRIC CONSTANT OF THE GaAs LATTICE

The relative dielectric constant er of high‐resistivity GaAs has been measured at 70.243 GHz as a function of temperature between 100 and 300°K. The measuring technique utilized a circular E field (TE°01) mode reflection‐coefficient bridge. Estimated relative and absolute accuracies of the measurements are ±0.2% and ±0.5%, respectively. The results are found to fit the equation er(T) = er(0){1 + αT} where er(0) = 12.73 ±.07 and α = (1.2 ± 0.1) × 10−4. At room temperature (295°K) the relative permittivity is er = 13.18 ±.07.

SEARCH FOR RESONANCE BEHAVIOR IN THE MICROWAVE DIELECTRIC CONSTANT OF GaAs

In a recent communication, Larrabee and Hicinbothem presented measurements of the dielectric constant of high‐resistivity GaAs showing a region of anomalous dispersion centered at 9.5 GHz. We have made similar measurements over the frequency range between 8.5 and 70 GHz but have not obtained their results. Our measurements indicate that the relative dielectric constant is independent of frequency in the microwave range and equal to 12.95 ± .10 at room temperature.

MICROWAVE PERMITTIVITY OF THE GaAs LATTICE AT TEMPERATURES BETWEEN 100°K AND 600°K

An earlier letter reported microwave (70.2 GHz) measurements of the relative permittivity er of high‐resistivity GaAs in the temperature range between 100° and 300°K. This letter extends the measurements to 600°K. Over the entire temperature range 100° < T < 600°K, the permittivity is observed to fit the expression er(T) = er(0){1 + αT}, where er(0) = 12.79 ± 0.10 and α = 1.0 × 10−4 deg−1.

Erratum: Plasma‐Filled Waveguide with Axial Magnetization. II. Scattering by a Section of Finite Length

The problem of mode conversion and scattering by a finite‐length section of magnetoplasma‐filled waveguide is formulated in matrix notation. This formulation becomes increasingly exact as the dimensions of the matrices (i.e., the number of modes considered) increases. The desired reflection‐ and transmission‐coefficient matrices are readily evaluated with a digital computer. Computations of TE010‐mode reflection coefficients indicate that good accuracy can be obtained with a fairly small (∼10) number of modes. Large errors result from considering only the incident (TE010) mode, however.