CN113270701A

CN113270701A - Miniaturized filtering phase shifter

Info

Publication number: CN113270701A
Application number: CN202110548708.0A
Authority: CN
Inventors: 施金; 聂怡; 张威; 徐凯; 郁梅; 张凌燕; 李宏伟
Original assignee: Nantong University; Nantong Research Institute for Advanced Communication Technologies Co Ltd
Current assignee: Nantong University; Nantong Research Institute for Advanced Communication Technologies Co Ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2021-08-17
Anticipated expiration: 2041-05-20
Also published as: CN113270701B

Abstract

The invention discloses a miniaturized filtering phase shifter, which comprises a main line structure and a reference line structure, wherein the main line structure and the reference line structure are the same in structure and are symmetrical about the horizontal direction; the main line structure and the reference line structure respectively comprise two quarter-wavelength coupling lines, two quarter-wavelength first microstrip lines, two second microstrip lines and two feeder lines, the left ends of the microstrip lines on the opposite inner sides of the two coupling lines are connected to form a V-shaped connecting structure, the right ends of the microstrip lines on the opposite inner sides of the two coupling lines are respectively connected with one first microstrip line, and the two first microstrip lines horizontally extend along the direction of the coupling lines; the two feed lines are correspondingly connected to the left ends of the microstrip lines on the opposite outer sides of the two coupling lines through a second microstrip line respectively; and the phase difference corresponding to the length difference of the second microstrip line of the main line structure and the reference line structure is used as a phase-shifting reference value of the phase shifter. The invention realizes the filtering phase shifter with multiple transmission zeros and has small size.

Description

Miniaturized filtering phase shifter

Technical Field

The invention relates to the field of microwave communication, in particular to a miniaturized filtering phase shifter.

Background

In a microwave system, the filtering and phase shifting functions are implemented by frequency selection and phase adjustment, respectively, and are usually implemented by a filter and a phase shifter, respectively. However, as the demand for integration and miniaturization of communication systems develops, it is more desirable to simultaneously implement the filtering function and the phase shifting function, i.e. the filtering phase shifter, by a single device, so as to reduce the number of devices and reduce the cost. Therefore, the filter phase shifter is an important research direction in the field of phase shifters. However, the filter phase shifter integrates two functions, so it is necessary to further improve the miniaturization effect and the filtering performance based on the function fusion.

Since 2017, there have been many approaches to filter phase shifter design. The phase shifter with the filtering function can be realized by adopting the coupling cascade of the half-wavelength stepped impedance U-shaped resonator or the multi-stage half-wavelength U-shaped resonator, but transmission zero points are not generated on two sides of a pass band, so that the filtering performance is not facilitated. The filtering phase shifter realized by the T-shaped resonator, the m-shaped transmission structure, the combination of the series-connection coupling line and the parallel-connection coupling line, the series-connection multi-stage fork-shaped transmission structure and the like can realize transmission zero points, but has larger size. The filtering phase shifter realized by combining the double-T-shaped transmission structure with the short-circuit branch knot can reduce the whole area to 0.1 lambda on the basis of realizing the transmission zero point_g ². However, due to the demands of integration and miniaturization, the size of the filter phase shifter needs to be further reduced.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the prior art, a miniaturized filtering phase shifter is provided, and the problems of few transmission zero points, large size and the like of the conventional filtering phase shifter are solved.

The technical scheme is as follows: a miniaturized filtering phase shifter comprises a main line structure and a reference line structure, wherein the main line structure and the reference line structure have the same structure and are symmetrical about a horizontal direction; the main line structure and the reference line structure respectively comprise two quarter-wavelength coupling lines, two quarter-wavelength first microstrip lines, two second microstrip lines and two feeder lines, the two coupling lines are symmetrically arranged around the horizontal direction, the left ends of the microstrip lines on the opposite inner sides of the two coupling lines are connected to form a V-shaped connecting structure, the right ends of the microstrip lines on the opposite inner sides of the two coupling lines are respectively connected with one first microstrip line, and the two first microstrip lines horizontally extend along the direction of the coupling lines; the two feed lines are correspondingly connected to the left ends of the microstrip lines on the opposite outer sides of the two coupling lines through a second microstrip line respectively; and the phase difference corresponding to the length difference of the second microstrip line of the main line structure and the reference line structure is used as a phase-shifting reference value of the phase shifter.

Has the advantages that: the invention realizes the filter phase shifter with multiple transmission zeros by connecting one end of a pair of opposite quarter-wave coupling lines and connecting the other end of the pair of opposite quarter-wave coupling lines with a quarter-wave microstrip line respectively, and has small size. The two quarter-wave coupling lines are connected in a V-shaped bending mode and are connected with the first microstrip line in a horizontally extending mode, and miniaturization of the phase shifter is facilitated.

Drawings

FIG. 1 is a schematic diagram of a filter phase shifter according to the present invention;

FIG. 2 is a graph of a frequency response simulation in which (a) is the matched response and (b) is the phase shifted response.

Detailed Description

The invention is further explained below with reference to the drawings.

As shown in fig. 1, a miniaturized filter phase shifter includes a main line structure and a reference line structure, which have the same structure and are symmetrical with respect to a horizontal direction. The main line structure and the reference line structure respectively comprise two quarter-wavelength coupling lines 1, two quarter-wavelength first microstrip lines 2, two second microstrip lines 3 and two feeder lines 4, the two coupling lines 1 are symmetrically arranged relative to the horizontal direction, the left ends of the microstrip lines on the opposite inner sides of the two coupling lines 1 are connected to form a V-shaped connecting structure, the right ends of the microstrip lines on the opposite inner sides of the two coupling lines 1 are respectively connected with one first microstrip line 2, and the two first microstrip lines 2 horizontally extend along the direction of the coupling lines 1; the two feed lines 4 are correspondingly connected to the left ends of the microstrip lines on the opposite outer sides of the two coupled lines 1 through one second microstrip line 3 respectively.

The second microstrip line 3 has a delay line function, the phase difference corresponding to the length difference between the main line structure and the second microstrip line 3 of the reference line structure is used as a phase shift reference value of the phase shifter, and the phase shift slope in the working frequency band is integrally controlled by the cascaded quarter-wavelength coupling line 1 and the quarter-wavelength first microstrip line 2, so that the stable phase shift covering the whole working frequency band is finally obtained.

The two first microstrip lines 2 which are connected with one end of the coupling line 1 in an end way and the second microstrip line 3 which is connected with the other end of the coupling line 1 in an end way enable the main line and the reference line of the phase shifter to generate 3 transmission zero points, the frequency selectivity of the phase shifter is improved, the filtering effect is obtained, and the main line and the reference line can obtain approximate 3-dB bandwidth by adjusting the impedance of the coupling line 1 of the main line and the reference line and the impedance of the first microstrip line 2, namely, the consistent filtering bandwidth and the effect are obtained. In addition, the 3-dB bandwidth of the phase shifter is increased along with the increase of the coupling coefficient of the coupling line 1 and is reduced along with the increase of the impedance of the first microstrip line 2; the phase shift bandwidth of the phase shifter is increased firstly and then reduced along with the increase of the coupling coefficient of the coupling line and the impedance of the first microstrip line; the two transmission zeros at the near end of the working frequency band are far away from the central frequency along with the increase of the coupling coefficient of the coupling line 1, and are close to the central frequency along with the increase of the impedance of the first microstrip line 2.

The following lists 45 ° and 90 ° cases of the present invention, whose main line and reference line structures are shown in fig. 1, respectively, achieve 45 ° and 90 ° phase shifts, with a center frequency of 3 GHz, and a frequency response simulation diagram is shown in fig. 2. For the reference line, the 3 dB relative bandwidth is 52% and the minimum insertion loss is 0.48 dB. For a 45 deg. phase shifter main line, the 3 dB relative bandwidth is 55%, the minimum insertion loss is 0.5 dB, and the corresponding electrical dimension is 0.5 λ_g×0.01 λ_g，λ_gThe guided wave wavelength corresponding to the center frequency. The 3 dB relative bandwidth of the main line of the 90 DEG phase shifter is 56%, minimum insertionThe input loss is 0.51 dB, and the corresponding electric size is only 0.7 lambda_g×0.01 λ_g. The bandwidth of the phase shift to achieve 45 ° ± 2.3 ° (90 ° ± 4.3 °) is 57% (58%). Therefore, the invention can obtain more consistent bandwidth while realizing different phase shifts, and the phase shift bandwidth can cover 3-dB passband. The reference line and the main line of the phase shifter both have a plurality of transmission zeros and a compact size. In this example, an RO4003C substrate was used, which had a dielectric constant of 3.38 and a loss angle of 0.0027.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A miniaturized filtering phase shifter is characterized by comprising a main line structure and a reference line structure, wherein the main line structure and the reference line structure have the same structure and are symmetrical about the horizontal direction; the main line structure and the reference line structure respectively comprise two quarter-wavelength coupling lines (1), two quarter-wavelength first microstrip lines (2), two second microstrip lines (3) and two feeder lines (4), the two coupling lines (1) are symmetrically arranged in the horizontal direction, the left ends of the microstrip lines on the opposite inner sides of the two coupling lines (1) are connected to form a V-shaped connecting structure, the right ends of the microstrip lines on the opposite inner sides of the two coupling lines (1) are respectively connected with one first microstrip line (2), and the two first microstrip lines (2) horizontally extend along the direction of the coupling lines (1); the two feed lines (4) are respectively and correspondingly connected to the left ends of the microstrip lines on the opposite outer sides of the two coupling lines (1) through a second microstrip line (3); and the phase difference corresponding to the length difference of the second microstrip line (3) of the main line structure and the reference line structure is used as a phase-shifting reference value of the phase shifter.