До питання про оптимізацію вузла з’єднання лінія-хвилевід з провідниковим елементом збуджувача

Abstract

Дослідження ґрунтується на методі синтезу вузла з’єднання лінія/хвилевід. За допомогою аналізу отримано залежності ширини смуги робочих хвиль вузла з’єднання від хвильового опору коаксіальної лінії для окремих значень вхідного імпедансу вузла на виході лінії. Відповідні криві мають максимуми для певних значень хвильового опору лінії. За змінного вхідного імпедансу можна встановити найбільше значення ширини смуги вузла з’єднання серед згаданих її максимумів. Такі криві дають змогу встановити оптимальні значення хвильового опору лінії, а також перевірити оптимальність структури вузла з’єднання. The given paper is based on the line/waveguide junction synthesis algorithm. The recommended there calculation expressions satisfy the loss free and tuning conditions for junction unit. The corresponding calculation formulas are deduced by oriented signal-flow graph method., and to the synthesis of loss free threeport with tuning reactance are used. Thus at the given middle wavelength the reflection from the junction ports are absent. For synthesis of junction unit by the algorithm mentioned above are necessary: 1) line wave resistance, 2) input impedance value at the line output port. The last quantity can be calculated by electrodynamic methods but with some difficulties. The input impedance is dependent on the longitudinal current distribution the exciter (vibrator) conductor, and current distribution on perimeter of that conductor cross section. It is possible to find the mentioned above distributions using the current approximation by wavelet functions. Spectral analysis method permits to find only the longitudinal distribution. Multifilament exciter structure modeling gives the unadequace mistakes. Input impedance calculation includes also the influence of exciter feed and his top load (vibrator exciter). It is a problem for such complex analysis, and result (input impedance) we get in numerical form. The experimentally measured quantity of input impedance can be used. for next junction synthesis. As synthesis result we get the value of tuning reactance and wavelength band of junction unit. But the found quantities are not optimum, that’s is why they can’t supply the maximal possible wavelength band for the given junction unit. The dependence of wavelength band from line wave resistance for given input impedance is presented in the paper graphically. That figure indicates the sharp influence of input resistance, and separately input reactance, on the junction wavelength-band width. Maximum of that band width arise at low value for negative input reactance. close to the critical quantity, when loss free condition can not be provided. For greater input reactance maximum of junction wave band width is almost independent from line wave resistance. Such the corresponding line wave resistance is to be realized. Enlargement of junction wave band width is possible by usage of tuning reactance with corresponding frequency characteristic, or analogous exciter structure. The input impedance value depends on the junction unit structure. Therefore above mentioned graphical figure includes the dependence on this structure. (Numerical quantity of input impedance carries that information). Thus the graphical chart can provide guidance for line wave resistance choosing, or junction unit structure choosing. It is to emphasize, that the mentioned above conclusions are valid for arbitrary waveguide, and various exciter structure.