SU1569921A1 - Microwave filter - Google Patents

Abstract

The invention can be used in frequency-selective microwave devices. The goal is to increase the slope of the slopes of the amplitude-frequency characteristic while maintaining high isolation outside the working frequency band. The microwave filter contains 1, 2, 3 traveling wave resonators that are electromagnetically coupled to one another, and the outermost of which are to input and output lines 4 and 5. Each of the three additional resonators 6, 7 and 8 running wave is electromagnetically coupled with the corresponding resonator 1, 2 and 3 traveling wave. The values of the electrical wavelengths of 1, 2, 3, 6, 7, and 8 traveling waves are set, at which the parasitic spectra are suppressed in a wide range of wavelengths. 2 Il.

Description

The invention relates to microwave technology and can be used in frequency selective devices.

The aim of the invention is to increase the slope of the slopes of the amplitude-frequency characteristics while maintaining a high isolation outside the working frequency band

1, a microwave filter is shown; in Fig.2 - the spectra of the eigenwaves of the resonators of the traveling wave and additional resonators of the traveling wave: a - resonators of the traveling wave in the absence of additional resonators of the traveling wave; b - the first additional resonator of the traveling wave; in - the second resonator of the traveling wave in the presence of the first additional resonator of the traveling wave; g - the second additional resonator of the traveling wave; d - the third resonator of the traveling wave in the presence of the first and second additional resonators of the traveling wave; e - the third additional resonator of the traveling wave; g - at the output of the third traveling wave resonator.

The microwave filter contains traveling-wave resonators Г ι3, electromagnetically coupled to one another and extreme ones (of which (.1,3) are electromagnetically connected to input 4 and output 5 lines.

The electric length of each resonator 1-3 is nft _in , where ft _e ”is the working wavelength in the resonator 1 3, and u = 3,5,7 (odd). Three additional resonators of a traveling wave 6-8 were introduced, each of which is electromagnetically coupled to a traveling wave resonator 1 (or 2, or 3), the electric length of the additional resonator 6 electromagnetically coupled to the traveling wave resonator 1 being half its perimeter, the perimeter of the additional the resonator 7 in P ^{ad is} smaller than the perimeter of the resonator 2, and the perimeter of the additional resonator 8 in _3 £ п_з_21_ η - t of the resistor 3, n + S “3 ~ - '

As elements of electromagnetic coupling between resonators 1 - 3 ,. additional resonators times smaller than the perimeter because S = 0,1,2,6 = 2,3,4;

- whole numbers.

- 8 and input 4 and output 5 lines are used directional couplers 9.

To reduce the size of the additional resonators 6-8 are located inside the resonator 1-3.

The microwave filter works as follows,

The microwave signal entering the input line 4 in the passband passes through the resonators G - 3 to the output line 5. The choice of the length of each resonator is n * D _c , where n ^ 3 provides an increase in the slope of the slopes of the amplitude-frequency characteristic ₀

The presence of additional resonators 6 - 8 in combination with odd η provides suppression of spurious spectra in a wide range of wavelengths (Fig, 2).

In FIG. 2a, the index ft indicates the spectrum of the operating wavelength. Since the resonators 1–3 of the traveling wave are chosen with the length nft, where η5 = 3rd is odd, their spectrum in the absence of additional traveling wave resonators contains other resonant lengths ft _n + 1,2 ,,. both smaller and larger than the working wavelength.

Introduction of the first additional traveling wave resonator 6, the spectrum of characteristic wavelength which is shown in Figure 2b ί ^»key Will because its perimeter is half the first traveling wave resonator 1 to implement the suppression of signals at the wavelengths;

'Ft ⁽ⁿ ' ft ⁰ ft * '

Τ '+ ¾ "A 4-5'” -I "-E ' ^β -5

The suppression of the signals in the traveling wave cavity resonator I at these wavelengths occurs because the additional traveling wave cavity 6 represents the cavity! traveling warriors coordinated load during critical electromagnetic connection with it,

Thus, the wavelength spectrum shown in Fig. 2c falls into the input of the traveling wave resonator 2. The introduction of the second 7 and third 8 additional traveling-wave resonators, the perimeter of which is selected in accordance with the above relations, allows us to suppress the wavelengths ft, (Fig.^2g’^d’^e'’ⁱⁿ result Therefore, at the output of the last traveling wave resonator 3, the spectrum contains only the fundamental wavelength and Ά⁽’’ 4 (FIG. 2g), which corresponds to a good separation of natural frequencies.⁵

The suppression of the intrinsic resonant wavelengths of at least six closest to the working wavelength 'λ ¹ * ¹ occurs only at odd η. | θ

To effectively suppress unwanted frequencies, additional resonators 6 - 8 are connected with those sections of resonators 1 - 3 in which the microwave signal passes in the direction from. 15 input line 4 to output line 5.

Thus, in the microwave filter, the slope of the slopes of the amplitude-frequency characteristic was increased while maintaining a high isolation outside the 20 working frequency band.

Claims (3)

Claim A microwave filter containing traveling-wave resonators 25, electromagnetically coupled to one another and the extreme ones of which are electromagnetically connected to the input and output lines, characterized in that, in order to increase the slope of the slopes of the amplitude-frequency characteristic while maintaining a high isolation outside the operating frequency band , the electric length of each traveling-wave resonator is n ^, where Ά is the working wavelength in the traveling-wave resonator, and η = 3, 5, 7 ..., and three additional traveling-wave resonators, each of which are electromagnets, are introduced but associated with a respective cavity traveling wave and has an electrical length less than the wavelength of the electron-symmetric resonator respectively 2, running ._z (n + 2) n + S 3 (n _-_ 2) _ η - t = 2, 3, 4, times, where S = 0, 1, 2, t „n + S η -'t a ---- and ------ are integers numbers. (Put. 2