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1982 Vol. 4, No. 3
Display Method:
1982, 4(3): 137-140.
Abstract:
A new concept about the matching of signal to a network is proposed. For an n-port microwave network, if all incident waves are proportional to the conjugates of oorresponding scattermg parameters of network S* ki(i = 1 n), then the ratio of the power of scattering wave at the k-th port to the sum of power of all incident waves reaehes the maximum. Using this concept, we find some problems may be simplified when microwave networks are studied. To illustrale application of the concept, a description of an ultrabroad-band line transformer and an antenna array is given in this paper.
A new concept about the matching of signal to a network is proposed. For an n-port microwave network, if all incident waves are proportional to the conjugates of oorresponding scattermg parameters of network S* ki(i = 1 n), then the ratio of the power of scattering wave at the k-th port to the sum of power of all incident waves reaehes the maximum. Using this concept, we find some problems may be simplified when microwave networks are studied. To illustrale application of the concept, a description of an ultrabroad-band line transformer and an antenna array is given in this paper.
1982, 4(3): 141-144.
Abstract:
A recursive algorithm for generating all hamiltonian cycles in maximum planar graphs of certain type has been proposed. For wagner graphs, the computed results may be represented by the following formula: M(p) =6+4(p-5), 5 p 20 where p is the order of the graph and M (p) is the total number of hamiltonian cycles. A theorem has been given and the correetness of the algorithm has been proved.
A recursive algorithm for generating all hamiltonian cycles in maximum planar graphs of certain type has been proposed. For wagner graphs, the computed results may be represented by the following formula: M(p) =6+4(p-5), 5 p 20 where p is the order of the graph and M (p) is the total number of hamiltonian cycles. A theorem has been given and the correetness of the algorithm has been proved.
1982, 4(3): 145-151.
Abstract:
In this artieal, the phase fluctuation of amplifier output signals caused by the direct eurrent power ripple is analysed quantitatively and the calculation formulas for the corresponding frequency stability characterized by time-domain Allen variance 2y() is derived.
In this artieal, the phase fluctuation of amplifier output signals caused by the direct eurrent power ripple is analysed quantitatively and the calculation formulas for the corresponding frequency stability characterized by time-domain Allen variance 2y() is derived.
1982, 4(3): 152-157.
Abstract:
Based on the experimental results obtained from both the measurement of material parameters and device responsivity, it is verified that the pyroeleetric responsivity figure of merit of LiNbO3 crystal, Mv is twice as high as that generaly acknowledged value. Furthermore, when the temperature rises, Mv slowly decreases rather than in-creases evidently with temperature as reported in certain literatures. In this paper, the output characteritics of LiNbO3 pyroeleetric detector which is irradiated by the high-power CW CO2 laser has been investigated. The results show that the maximum power density at which the output characteristics of LiNbO3 detector begin to deviate from linear range far exceeds that of LiTaO3 detector under the same conditions. We have carefully measured the intrinsic dielectric loss tgd of LiNbO3 crystal. The value obtained can be used to estimate the detectivity limit of LiNbO3 pyroelectric detector. Detailed analysis proves that, for producing the pyroelectric detector with background limited performance, its figure of merit of LiNbO3 crystal is favorable, and no loss than those of most commonly used materials, such as TGS.
Based on the experimental results obtained from both the measurement of material parameters and device responsivity, it is verified that the pyroeleetric responsivity figure of merit of LiNbO3 crystal, Mv is twice as high as that generaly acknowledged value. Furthermore, when the temperature rises, Mv slowly decreases rather than in-creases evidently with temperature as reported in certain literatures. In this paper, the output characteritics of LiNbO3 pyroeleetric detector which is irradiated by the high-power CW CO2 laser has been investigated. The results show that the maximum power density at which the output characteristics of LiNbO3 detector begin to deviate from linear range far exceeds that of LiTaO3 detector under the same conditions. We have carefully measured the intrinsic dielectric loss tgd of LiNbO3 crystal. The value obtained can be used to estimate the detectivity limit of LiNbO3 pyroelectric detector. Detailed analysis proves that, for producing the pyroelectric detector with background limited performance, its figure of merit of LiNbO3 crystal is favorable, and no loss than those of most commonly used materials, such as TGS.
1982, 4(3): 158-167.
Abstract:
The principle of a TWT oscillator using a YIG as feedback element is analyzed and the tunning performance is derived also. It shows also that this kind of oscillator can oscillate in a rather wide frequency range but the oscillating frequency is separated in bands. There are forbidden regions for oscillating. Under ordinary conditions, the forbidden regions are almost equal to the oscillating regions. The results of experiments are in agreement with the theory. This shows that there still are problems if one uses the TWT-YIG oscillator as a broad-band sweeping oscillator.
The principle of a TWT oscillator using a YIG as feedback element is analyzed and the tunning performance is derived also. It shows also that this kind of oscillator can oscillate in a rather wide frequency range but the oscillating frequency is separated in bands. There are forbidden regions for oscillating. Under ordinary conditions, the forbidden regions are almost equal to the oscillating regions. The results of experiments are in agreement with the theory. This shows that there still are problems if one uses the TWT-YIG oscillator as a broad-band sweeping oscillator.
1982, 4(3): 168-174.
Abstract:
In this paper, from the microwave network equivalent circuit point of view, we propose a design method of output circuit of broadband klystron which is made of two stage filters. According to this method, we can get a group of design parameters corresponding to the broadest bandwidth with given real part of interaction impedance. It is proved experimentally that this method is feasible.
In this paper, from the microwave network equivalent circuit point of view, we propose a design method of output circuit of broadband klystron which is made of two stage filters. According to this method, we can get a group of design parameters corresponding to the broadest bandwidth with given real part of interaction impedance. It is proved experimentally that this method is feasible.
1982, 4(3): 175-185.
Abstract:
This paper presents the structural design of two types of nonintercepting gridded gun (i.e. unigrid and tetrode nonintereepting gridded gun). The basic method of the cathodegrid structural design and calculating method of the cathode geometrie usage factor are given. Hence the optimum grid mesh numbers, the dimensions of the grid cells and grid web width are reasonably determined. Also this paper presents the me-thods of machining and aligning the grid for the cathode-grid assembly. The phenomena of breakdown in the electron gun is discussed.
This paper presents the structural design of two types of nonintercepting gridded gun (i.e. unigrid and tetrode nonintereepting gridded gun). The basic method of the cathodegrid structural design and calculating method of the cathode geometrie usage factor are given. Hence the optimum grid mesh numbers, the dimensions of the grid cells and grid web width are reasonably determined. Also this paper presents the me-thods of machining and aligning the grid for the cathode-grid assembly. The phenomena of breakdown in the electron gun is discussed.
1982, 4(3): 186-191.
Abstract:
Activation proeess of an oxide eathode on a Ni-W-Mg substrate was investigated using auger electron spectroscopy (ABS) and X-ray protoelectron spectroscopy (XPS).ABS and XPS results show that the relative surfaee compositions of alkaline earth metal of an oxide eathode have changed during various states of activation. The surfaee layer of a well activated eathode consists of (Ba, Sr, Ca) O+Ba.
Activation proeess of an oxide eathode on a Ni-W-Mg substrate was investigated using auger electron spectroscopy (ABS) and X-ray protoelectron spectroscopy (XPS).ABS and XPS results show that the relative surfaee compositions of alkaline earth metal of an oxide eathode have changed during various states of activation. The surfaee layer of a well activated eathode consists of (Ba, Sr, Ca) O+Ba.
1982, 4(3): 192-197.
Abstract:
The heat dissipation of anodes or collectors is one of the essential problems in the design of high power electron device. In recent twenty years high efficient vaporization cooling structure has been developed, but its design is still done by means of simulation or empirically. In this paper, a mathematical model for the vaporization cooling eleetrode and its solving method are provided. The nonlinear and multi-valued proporties of this mathematical physical equation are discussed. As an example, a numerical solution of inner temperature field in a typical vaporization cooling electrode, an anode of high power electron tube has been given with digital computer. On the basis of these results, the design of vaporization cooling electrode and estimation of its heat dissipation capability are possible.
The heat dissipation of anodes or collectors is one of the essential problems in the design of high power electron device. In recent twenty years high efficient vaporization cooling structure has been developed, but its design is still done by means of simulation or empirically. In this paper, a mathematical model for the vaporization cooling eleetrode and its solving method are provided. The nonlinear and multi-valued proporties of this mathematical physical equation are discussed. As an example, a numerical solution of inner temperature field in a typical vaporization cooling electrode, an anode of high power electron tube has been given with digital computer. On the basis of these results, the design of vaporization cooling electrode and estimation of its heat dissipation capability are possible.
1982, 4(3): 198-200.
Abstract:
This note gives a method to find all the 1-factors and 1-factorial connections of a flow graph. Let (D) be the set of all subgraphs of a given diagraph G(V, E) and (H) be the set of all subsets of (D). For h1, h2 (H), a multiplication operation being called star is denoted by the symbol * and is defined in the following: h1,*h2 ={xy/xh1, yh2, and deg+xy(i)2, deg-xy(i)2}. Theorem Let G(V, E) be a diagraph with vertex set V={1, 2,,}, and let Sk={(k, t)/(k, t) E, t V}. Then all the 1-factors of G(V,E) can be determined by the product of Sk as follows:C=S1*S2**S Obviously, if G(V,E) is replaced by G(V, E) is replaced by G(V, E)U(j, i), (j, i) E, then the product gives all the 1-factorial connections from em to j of the diagraph G(V, E).
This note gives a method to find all the 1-factors and 1-factorial connections of a flow graph. Let (D) be the set of all subgraphs of a given diagraph G(V, E) and (H) be the set of all subsets of (D). For h1, h2 (H), a multiplication operation being called star is denoted by the symbol * and is defined in the following: h1,*h2 ={xy/xh1, yh2, and deg+xy(i)2, deg-xy(i)2}. Theorem Let G(V, E) be a diagraph with vertex set V={1, 2,,}, and let Sk={(k, t)/(k, t) E, t V}. Then all the 1-factors of G(V,E) can be determined by the product of Sk as follows:C=S1*S2**S Obviously, if G(V,E) is replaced by G(V, E) is replaced by G(V, E)U(j, i), (j, i) E, then the product gives all the 1-factorial connections from em to j of the diagraph G(V, E).
