SU1062816A1 - Tunable resonator - Google Patents

Abstract

A REJECTABLE RESONATOR containing a length of coaxial line, the outer and inner conductors of which are short-circuited at one end and loaded with a variable capacitor at the other end, characterized in that, in order to expand the frequency tuning range, the internal capacitor is connected to the variable capacitor connection point annular groove. (L O5 S 00 05

Description

The invention relates to a microwave technique and can be used as a tunable resonant circuit of generators or amplifiers. A tunable resonator is known, containing a segment of a coaxial line, short-circuited at one end, and a paraglally connected capacitor of the first ::; This tunable resonator has a narrow frequency tuning range. The closest technical solution to the proposed one is a tunable resonator containing a length of coaxial line, the outer and inner conductors are short-circuited at one end and loaded with a variable capacitor at the other end 2. The known resonator is more range, but it is not enough; the wide frequency tuning range is often you .. The purpose of the invention is to extend the frequency tuning range. To achieve the goal, in a tunable cavity containing a coaxial line, the outer and inner conductors of which are shorted from one end and loaded by a variable capacitor from the other end, an annular groove is made in the inner conductor relative to the connection point of the variable capacitor. The drawing shows a tunable resonator design. The tunable resonator contains a segment of a coaxial line, the outer 1 and inner 2 conductors of which are short-circuited at one end by the plate 3, and at the other end loaded with a capacitor 4 changes of capacitance. In the internal conductor 2 relative to the connection point of the capacitor 4, an annular groove 5 is made. The tunable resonator can be represented as a reactive circuit with an input resistance X (Us) and a variable capacitor 4 C. Resonant frequencies of the system C0 |, k 1,2,., , completely depend on these elements: - X (cx),

The range at the resonant frequency uj., Is characterized by the ratio between the frequency overlap factor 60 and the capacitance overlap factor J Tsadkh / S; For a given value of rR - in a more range system, a larger value K is achieved. 65

1 +

Making an annular groove 5. In the inner conductor 2, the part of the inner conductor i 2 of length 1 .. will be represented. On the other hand, the range is characterized by the degree to which the variable capacitance C influences the resonant frequencies. In a more band system, the relative change in capacitance will lead to a greater relative change in the resonant frequencies / a w c /. Let us consider the value of which is the sensitivity of resonant frequencies to a change in variable capacitance C. The minus sign in expression (2) reflects the fact that an increase in C leads to a decrease. The expediency of introducing sensitivity (2) is due to the following circumstances. will result in a larger value of k being reached for a given ae. On the other hand Sj. associated with the input resistance of the reactive circuit X (y), which follows from the expressions (1) and (2): qh, d / X I. tOK)) dX (w), X (uj b - in -r /, ., j 1 X (w) th Expression (3) shows that the sensitivity S j is a characteristic of a circuit included in an oscillatory system, which is determined as a function of the sensitivity of the reactive circuit LJ-idfdX (w); (br) 1 + W J d W X (uu) O Expression (4) sets in accordance with the input resistance of the reactive circuit the sensitivity function of the resonant frequencies of the oscillating system. For a tunable resonator containing a short-circuit The length of the transmission line is 6 in length with the characteristic impedance W, the input impedance X (w) is equal to X (s) W tg Ы - where V is the velocity of propagation of an electromagnetic wave in a line. Therefore, the input resistance X „(w) of such a circuit is determined by the expression

in.

X, (to) W tguj: 5 W,., Tgu)

On the basis of expression (4), it corresponds to a sensing function. Since calculations show that S, (;) 7 S (ui) for any choice

5 „and Wp, this proves that the presence of an annular groove 5 in the inner conductor 2 increases the sensitivity of the main resonance frequency to changes in the variable capacitance of the capacitor 4, which allows increasing the tuning range at the same value of the overlap in variable capacitance C. (6) 5 The proposed tunable resonator has a wider frequency tuning range in comparison with the known one, for example, when k 2, the known one has ar 8, .47, and has a pre-tuned resonator of 6.53–5.89 depending on Wf, / w and ff, / and-at uve ichenii Wn / W value (monotonically reduced.

Claims (1)

A tunable resonator, comprising a segment of a coaxial line, the outer and inner conductors of which are short-circuited at one end and loaded with a variable capacitor at the other end, characterized in that, in order to expand the frequency tuning range, an annular ring is made in the inner conductor relative to the connection point of the variable capacitor groove.