A notch filter for 140 GHz microwave radiation

The construction of a notch-filter for 140 GHz with very low passband insertion loss is described. It is based on a single-mode rectangular waveguide and cylindrical cavities matched to it. The typical transmission characteristic is also presented.     

Precision broadband wavemeter for millimeter and submillimeterrange

A precise, broadband, Fabry-Perot wavemeter has been designed and built to measure wavelengths in the millimeter and submillimeter range. The design of the wavemeter is novel in that it enhances the fundamental mode over a wide band and permits determination of the exact longitudinal index of the mode. With the use of an exact mode number in wavelength calculations, high measurement accuracies, to the extent permissible by the quality factor of the resonator, can be obtained. The wavemeter was tested by measuring well-known spectral lines of the OCS molecule in the frequency range of 72-607 GHz. Measurement of 24 OCS lines demonstrated an accuracy of better than 2×10^-5 in relative units and 0.87×10^-5 in rms units for frequency/wavelength. A discussion of further development and automation of the wavemeter is included     

A method to measure dielectric parameters in 5–0.5 millimeter wavelength band

The method to measure parameters of dielectric plates by placing them into the Fabry-Perot resonator is modified to provide, relative accuracies: for the resonance frequency of the plate 10^?6; for the refractive index and the plate thickness 10^?4–10^?5; for the loss tangent 5%. Tje values of loss tangent which can be measured are from 10^?6 to 10^?1. The device calibration is performed by a gas frequency standard in 5–0,5 mm wavelength band.     

A bench for precision measurement of rejection-filter frequency characteristics in the 2-mm wave band

The circuit and parameters of a measuring bench for precision measurement of the amplitude-frequency responses of four-pole networks in the 140-GHz band are discussed. Owing to the use of a sensitive superheterodyne receiver and radiation sources stabilized in frequency by a quartz frequency standard, the measuring bench provides a dynamic range no less than 120 dB and accuracy of frequency reading better than 1 MHz.     

A 110 GHz ozone radiometer with a cryogenic planar Schottky mixer

A total power radiometer for monitoring the stratospheric ozone spectral line at 110 GHz is presented. Special features such as a cooled planar Schottky mixer as the front end and efficient reduction of standing waves in the quasi-optics are discussed in detail. The noise temperature of the receiver is 530 K (single sideband), and the total bandwidth of the receiver is 1 GHz. A dual acoustooptical spectrometer is used for the signal detection