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1984 Vol. 6, No. 2
Display Method:
1984, 6(2): 89-95.
Abstract:
Through the analysis and synthesis of data obtained from barium containing thermionic cathodes, especially those by modern surface analysis technique, we have come to a unified theory-the dynamical surface emission center model. Barium adsorbed on the surface of alkaline earth metal oxides in case of oxide cathode or of aluminate, tungstate etc. in case of dispenser cathode may form the emission center. Its size should be large enough to screen off the attractive field produced by the substrate, but small enough to facilitate the transport of electrons from the substrate to the emitting center. The compositions and the dynamical characters of the surface emission center are also discussed.
Through the analysis and synthesis of data obtained from barium containing thermionic cathodes, especially those by modern surface analysis technique, we have come to a unified theory-the dynamical surface emission center model. Barium adsorbed on the surface of alkaline earth metal oxides in case of oxide cathode or of aluminate, tungstate etc. in case of dispenser cathode may form the emission center. Its size should be large enough to screen off the attractive field produced by the substrate, but small enough to facilitate the transport of electrons from the substrate to the emitting center. The compositions and the dynamical characters of the surface emission center are also discussed.
1984, 6(2): 96-106.
Abstract:
The traditional requirements for the antenna are reviewed. Under such background and on the basis of previous work, the subjects concerning the phase of antenna beam and the current distribution of antenna aperture, such as the phase reference point, the trans-formation relationship of the far field patterns corresponding to different phase reference points of an antenna, the null level and phase difference between the adjacent beams, and the resolution of current distribution of the linear array are systematized and discussed. The general condition of the beam in phase and the condition of the symmetric beam of a continuous linear array are given and proved theoretically. Some theorems are proposed, and the whole is termed the phase theory of antenna beam.
The traditional requirements for the antenna are reviewed. Under such background and on the basis of previous work, the subjects concerning the phase of antenna beam and the current distribution of antenna aperture, such as the phase reference point, the trans-formation relationship of the far field patterns corresponding to different phase reference points of an antenna, the null level and phase difference between the adjacent beams, and the resolution of current distribution of the linear array are systematized and discussed. The general condition of the beam in phase and the condition of the symmetric beam of a continuous linear array are given and proved theoretically. Some theorems are proposed, and the whole is termed the phase theory of antenna beam.
1984, 6(2): 107-116.
Abstract:
Antenna array pattern null-steering is one of the important current topics in array synthesis theory, because it is very effective in suppressing interfering signals. Thus the problem of forming nulls in the radiational pattern of three-dimentional arrays is discussed. This paper discusses the following aspects of the said arrays: The essential relations of forming multi-nulls are analysed by the method of vector space; The method of forming multi-null regions is presertted by the concept of null region in terms of the extended property of null itself the beam-resolvent formulation of radiational pattern of multi-null steering is derived; numerical results are included and discussed. The beam-resolvent formulation is analogous to the one of adaptive arrays.
Antenna array pattern null-steering is one of the important current topics in array synthesis theory, because it is very effective in suppressing interfering signals. Thus the problem of forming nulls in the radiational pattern of three-dimentional arrays is discussed. This paper discusses the following aspects of the said arrays: The essential relations of forming multi-nulls are analysed by the method of vector space; The method of forming multi-null regions is presertted by the concept of null region in terms of the extended property of null itself the beam-resolvent formulation of radiational pattern of multi-null steering is derived; numerical results are included and discussed. The beam-resolvent formulation is analogous to the one of adaptive arrays.
1984, 6(2): 117-124.
Abstract:
The odd mode and even mode propagation constants of uniformly coupled trapped image waveguides are calculated by using the effective dielectric constant approach and the surface impedances matching. The theoretical characteristics of a coupler made of coupled trapped image waveguides are analysed and they can be used as a foundation for design of this kind of coupler.
The odd mode and even mode propagation constants of uniformly coupled trapped image waveguides are calculated by using the effective dielectric constant approach and the surface impedances matching. The theoretical characteristics of a coupler made of coupled trapped image waveguides are analysed and they can be used as a foundation for design of this kind of coupler.
1984, 6(2): 125-136.
Abstract:
YIG tuned oscillator combines linear broad band tunability and low noise characteristics. is used as VCO of PLL in the partial coverage type microwave synthesis experiment. More than ten thousand discrete frequencies from 2GHz to 4GHz, having the stability and acuracy of an ultra-stable quartz crystal oscillator, have been synthesized successfully. The influence of magnetic field hysteresis on the nonlinear performance of PLL is studied theo-retically. Three formulas of YIG phase locked loop with magnetic field hysteresis have been derived by analytical approximation method. They are the average frequency difference formula, the acquisition time formula and the acquisition range formula. The formulas have clear physical meanings. the experiment shows that the acquisition range formula agrees with the result of actual measurement. approximately.
YIG tuned oscillator combines linear broad band tunability and low noise characteristics. is used as VCO of PLL in the partial coverage type microwave synthesis experiment. More than ten thousand discrete frequencies from 2GHz to 4GHz, having the stability and acuracy of an ultra-stable quartz crystal oscillator, have been synthesized successfully. The influence of magnetic field hysteresis on the nonlinear performance of PLL is studied theo-retically. Three formulas of YIG phase locked loop with magnetic field hysteresis have been derived by analytical approximation method. They are the average frequency difference formula, the acquisition time formula and the acquisition range formula. The formulas have clear physical meanings. the experiment shows that the acquisition range formula agrees with the result of actual measurement. approximately.
1984, 6(2): 137-146.
Abstract:
By the use of the concept of reactance compensation, the integrated series bulk effect oscillator, being compensated to increase the tuning bandwidth is reported. In C-band, the relative bandwidth is greater than 10 percent,the output power is greater than 30 mW, and the change of power is less than 3 dB. The analytical expression of tuning bandwidth and the design of oscillator circuit are given.The combined microstrip with coaxial line structure is adopted for the oscillator. Shunt resonance is changed into serier resonance. The integrated wideband bulk effect oscillator has a wide application in radar and radio communication.
By the use of the concept of reactance compensation, the integrated series bulk effect oscillator, being compensated to increase the tuning bandwidth is reported. In C-band, the relative bandwidth is greater than 10 percent,the output power is greater than 30 mW, and the change of power is less than 3 dB. The analytical expression of tuning bandwidth and the design of oscillator circuit are given.The combined microstrip with coaxial line structure is adopted for the oscillator. Shunt resonance is changed into serier resonance. The integrated wideband bulk effect oscillator has a wide application in radar and radio communication.
1984, 6(2): 147-155.
Abstract:
The influence of the phase distribution function on the coupled impedance for a coupled cavity structure is investigated and calculated. The results calculated by computer shows that for different phase distribution function s the negative first harmonie coupled impedance may differ up to a factor of two.
The influence of the phase distribution function on the coupled impedance for a coupled cavity structure is investigated and calculated. The results calculated by computer shows that for different phase distribution function s the negative first harmonie coupled impedance may differ up to a factor of two.
1984, 6(2): 156-165.
Abstract:
The various applications of a-Si:H films are discussed in this paper.a-Si:H solar cells are the most important devices of amorphous silicon, and the major subject at present, is to improve the device parameters, especially to increase the conver-sion efficiency. The prospect may be bright for its photosensitive effects to record and store picture informations on a-Si:H films (e.g. image pick-up tube and electrophotography). The a-Si:H integrated circuits may have attractions for the easier realization of its three-dimensional structure and large area. The large area display of LC driven by a-Si:H FETs and the probability of using electroluminecence of a-Si:H for the same purpose merits attention. Other a-Si:H diodes, such as a-Si:H rectifier and detector, are also quite valuable.
The various applications of a-Si:H films are discussed in this paper.a-Si:H solar cells are the most important devices of amorphous silicon, and the major subject at present, is to improve the device parameters, especially to increase the conver-sion efficiency. The prospect may be bright for its photosensitive effects to record and store picture informations on a-Si:H films (e.g. image pick-up tube and electrophotography). The a-Si:H integrated circuits may have attractions for the easier realization of its three-dimensional structure and large area. The large area display of LC driven by a-Si:H FETs and the probability of using electroluminecence of a-Si:H for the same purpose merits attention. Other a-Si:H diodes, such as a-Si:H rectifier and detector, are also quite valuable.
1984, 6(2): 166-171.
Abstract:
An improved method using crystal oscillator for measuring the evaporation rate of ca-thodes is proposed, in which the distance between the crystal (substrate) and the cathode (source) is smaller than usually maintained. Thus more evaporation products from the cathode can be received by the crystal, and consequently the method can be used for measuring lower evaporation rate. Formulae for calculating the evaporation rate are derived, and the precision of the these is given. In this paper a method to prevent the resonant frequency change caused by the change of temperature is also given. The experimental result shows that one Hertz resonant frequency shift can be detected while the oscillation frequency is 5 MHz.
An improved method using crystal oscillator for measuring the evaporation rate of ca-thodes is proposed, in which the distance between the crystal (substrate) and the cathode (source) is smaller than usually maintained. Thus more evaporation products from the cathode can be received by the crystal, and consequently the method can be used for measuring lower evaporation rate. Formulae for calculating the evaporation rate are derived, and the precision of the these is given. In this paper a method to prevent the resonant frequency change caused by the change of temperature is also given. The experimental result shows that one Hertz resonant frequency shift can be detected while the oscillation frequency is 5 MHz.
1984, 6(2): 172-175.
Abstract:
The interdiffusion of p-InP/TiPdAu at interface has been investigated by Auger electron spectroscopy (AES). The surface morphology of heat treatment samples are observed. The specific contact resistance as a function of heat treatment temperatures for the p-InP/ TiPdAu systems is also given.It is found that the interdiffusion of Au, In, P occurs during the heat treatment of p-InP/TiPdAu. The Pd layer as a diffusion barrier plays an important role. The interdiffusion, morphology and specific contact resistance for heat treatment samples of p-InP/TiPdau have interconnection and strong dependence on each other. The TiPdAu layers are used as p-electrodes for InGaAsP/InP double heterojunction light emitting diodes. The p-electrode has good stability.
The interdiffusion of p-InP/TiPdAu at interface has been investigated by Auger electron spectroscopy (AES). The surface morphology of heat treatment samples are observed. The specific contact resistance as a function of heat treatment temperatures for the p-InP/ TiPdAu systems is also given.It is found that the interdiffusion of Au, In, P occurs during the heat treatment of p-InP/TiPdAu. The Pd layer as a diffusion barrier plays an important role. The interdiffusion, morphology and specific contact resistance for heat treatment samples of p-InP/TiPdau have interconnection and strong dependence on each other. The TiPdAu layers are used as p-electrodes for InGaAsP/InP double heterojunction light emitting diodes. The p-electrode has good stability.
1984, 6(2): 176-180.
Abstract:
An inductive switched-capacitor (i.e., terminal-inverter SC) oscillator is described in this paper. It is found that the amplitude equation is independent of the capacitor ratio and high-frequency components introduced by the sampling process are about 50 percent lower than those of a parallel SC oscillator.
An inductive switched-capacitor (i.e., terminal-inverter SC) oscillator is described in this paper. It is found that the amplitude equation is independent of the capacitor ratio and high-frequency components introduced by the sampling process are about 50 percent lower than those of a parallel SC oscillator.
