The operator method for the determination of dyadic Green s functions is presented by the extention of concepts of vector space to dyadic space, and the new expression for the dyadic magnetic wave equation is derived strictly by using the theory of distribution. As an exam-ple, the dyadic Green s functions in generalized cylindrical waveguides are given.

An analysis method of microwave four-port circuits by using the transfer matrix is presented. The mathematical models of several basic circuit elements and expressions of net-work functions for microwave four-port circuits are given. Furthermore a small general program is also presented which is capable of analysing and optimizing a group of directional couplers, balanced transistor amplifiers and electrically tuned attenuators.

An effect of the transfer noise in the CCD on the output signal-to-noise ratio of the cor-relator is analyzed theoretically. The efficiency of multichannel parallel operation for the CCD is designated. Finally, the experimental results of double channel parallel operation for the CCD are given, and the practicability of this method is demonstrated.

A fabrication procedure for large area germanium photodiodes has been demonstrated and the measuring methods on characteristics of spectral response, quantum efficiency, fre-quency response and I-V for this device have been described. At 1.3 μm wavelength, the responsibility and the quantum efficiency are 0.47 A/W and 45%, respectively. The frequ-ency response of large area germanium photodiodes is about 100kHz. When bias voltage V_B is in the range of 5V at room temperature (12℃), the dark current density of the fabricated diodes is 23×10^-6 A/cm²(Φ=7.5mm). Typical dark current and I-V dependences on temperature were studied for the large area germanium photodiodes in the range of 20—26℃. We have also analysed and discussed these experimental results.

The effect of the monochromaticity of relativistic electron beam's energy on the small signal gain of free electron lasers is analyzed. For a certain pumping field, there is a critical energy divergency, over which the small signal gain will become negative. The shorter the wavelength and the longer the magnification length, the higher is the requirement of energy monochromaticity of electron beam for laser amplifiers. But the requirement of monochromaticity of electron beam for laser oscillators is much lower.

A kind of non-intercepting gridded gun is described, in which an annular grid-mesh type shadow grid is immediately embedded in the cathode. A simplified two-dimensional ma-thematical model is presented for computer aided design. Through investigation of the resu-Its of this computation a method of designing such a gun is presented. An experiment on a non-intercepting gridded gun with a perveance of 0.9 μP is carried out. The obtained resu-Its prove that the computer program proposed here satisfies fully the design demand of this kind of non-intercepting gridded gun.

Electron initial velocity distribution of two kinds of parctical thermionic cathodes are studied with "pre-acclerating-post-deaccelerating type retarding field method. Based on the theory of dynamical surface emission centers, the phenomenon, i.e. the electron initial velocity distribution of the oxide-coated cathode splits into spectrums under strong pulse ele-ctric field, is explained.

Based on the equation of the Fresnel-Kirchhoff scalar diffraction field, the expressions of the impulse response of one-dimensional end-fed array antenna and the impulse responses of the antenna to the narrow-band radio-frequency signals and their envelopes are derived for arbitrary aperture amplitude-distributions.

According to the recently developed travelling wave interaction concepts, a TW FET with suitable electrode structure for a monolithic realization has been designed and investi-gated by a microstrip line hybrid model together with individual FETs. A coplanar meander line slow wave electrode system was chosen, since it can be easily integrated into a monolithic FET structure. The active length of the model was 3 guided wave length long. With 21 individual FETs the output power of the model was higher by more than one order in magnitude as compared to an individual FET. A rather flat gain characteristic with broad-band-width of 1:15 was obtained. The small signal S parameters showed useful values. The RF field distribution along the active meander line electrodes was measured. The distribution reveals the TW interaction nature. The phase shift and two tone third order intermodulation with the input power level were also observed. No efforts had been spent to optimize the model design, but the measured characteristic was still attractives; there is much room for improvement in performance of the TW FET.

The results of a study in the diffusion length of holes in a-Si:H by measuring the sur-face photovoltage of the metal (Ni) Schottky barrier is reported. The change of field-assis-ted hole transport with bias light was observed. It is believed that measurement of diffusion length by this method may become a useful way of detecting and improving the quality of a-Si:H.

In this paper the ability of antireflection film to withstand the destructive effect of Laser radiation in the neighborhood of 10μm is investigated. Some methods for improving the destructive threshold of the antireflection films are proposed.

A SmPrCo PM focusing system for 3 cm klystron is reported. The magnetic gap of the magnetic system is 67.3 mm. The maximum field intensity in the gap is 2700Gs. The fluc-tuation of the field intensity is 4%, the weight of the SmPrCo magnet is only 5 kg. The total weight of the magnetic system is 8.6 kg. The magnetic system has been used for a 50 kW klystron, and the results obtained are satisfactory. The beam transmission of the klystron is above 98%.

In this paper, a new scheme for designing a 8 mm high power pulse coaxial magnetron Is proposed. Design equations and experimental results are given.