SU1494076A1 - Band-pass filter - Google Patents

Abstract

The invention relates to microwave technology. GOAL - IMPROVE SELECTIVITY. THE STRIP FILTER CONTAINS DIELECTRIC SUBSTRATES 1 AND 2, GROUNDING BASE 3, SLIT 4, BANDS to the output of another PP 5, energizing slot 4. The slots 4 of length L and the segments 5 and 7 of length L, which are electromagnetically connected to one another, provide a short circuit on the microwave current of segment 5 at the point of crossing with slot 4, which in this point is open on the microwave current. This ensures the passage of the microwave signal at the end of 8 without reflections. The presence of electromagnetically coupled PP 5 and 7, which have a quarter-wavelength L and short-circuited at the end, provides two damping poles located on opposite sides of the transmission frequency. This is due to the difference in the phase velocities of the even and odd types of waves. In this regard, the steepness of the amplitude-frequency x-ki bandpass filter increases sharply. 2 Il.

Description

4 o

ABOUT

3149

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

The purpose of the invention is to increase selectivity.

Fig. 1 shows the construction of a bandpass filter with short-circuited strip conductors; Fig. 2 illustrates a bandpass filter design with open strip conductors.

The bandpass filter contains two dielectric substrates 1 and 2, between which is placed the grounding base 3, in which the gap 4 is filled, short-circuited at the ends and the length If of which is a multiple of the integer half-wavelength, there is a strip conductor 5 on the outer side of each dielectric substrate 1 and 2, intersecting with slit 4 at a distance of 1 equal to a quarter of the wavelength from one of its ends, with the first end 6 of each strip conductor being an input and an output, respectively. On the outer side of each dielectric substrate 1 and 2 there is an additional strip conductor 7, electromagnetically connected with strip conductor 5 along its entire length and the first end 8 of which is opposite the slit 4 and open and the second End 9 of the additional strip conductor 7 and the second end 10 of the strip conductor 5 lying on a single straight A-A and is either grounded and the additional strip conductor 7 has a quarter-wave length, Ij, or is open and the additional strip conductor has a half-wave length.

In a particular implementation, the length If of the slit 4 may be equal to the wavelength, as in FIG. 1, and half the wavelength as in FIG. 2.

The bandpass filter works as follows

The microwave signal arriving at the input (end) 6 of one of the strip conductor 5, in the passband passes to the output of another strip conductor, the gap 4,

The slots 4 of length 1, “and the lengths of the stripline conductor 5 and the additional stripline conductor 7 of length 1, which are electromagnetically connected with one another, provide short

.-

20

25

five

 O 5, 35 40

45,

gp,

thirty

microwave current short circuit of the strip of conductor 5 at the point of crossing with slot 4, which at this point is open for the microwave current, and thus ensures the passage of the microwave signal at the output (end) 8 without reflections.

Claims (1)

The presence of an electromagnetically coupled strip conductor 5 and an additional strip conductor 7, for example, having a quarter-wavelength T and short-circuited at the end, provides two attenuation poles located on opposite sides of the transmission frequency, which occurs due to the difference between the phase storii of even and odd wave types, In this connection, the steepness of the amplitude-frequency characteristic of the bandpass filter increases sharply. A similar result is obtained with a half-wavelength length of the additional strip conductor 7 and, accordingly, the same length of the strip conductor 5 in the segment. (since their open ends 9 and 10 lie on the same straight line AA), the formula from finding A band-pass filter containing two dielectric substrates, between which a grounding base is placed, in which a slot is made, is short-circuited at the ends, and on the outer side of each dielectric support, there is a strip conductor crossed with a slot at a distance of a quarter of the length waves from one of its ends, wherein the first end of each strip conductor is an output and an input, respectively, characterized in that, in order to increase the selectivity, on the outside of each dielectric base An additional strip conductor is placed electromagnetically connected with the strip conductor on its entire spine, and the first end of which is located opposite the slot, whose length is a multiple of the whole number of half-waves, and is open, and the second ends of the strip conductor and the additional strip conductor lie on one straight and either grounded and the extra strip conductor has a quarter-wave length, or open and the extra strip conductor has a half-wave length. FIG. 2