CN-121529146-B - Single-layer microstrip coupler

CN121529146BCN 121529146 BCN121529146 BCN 121529146BCN-121529146-B

Abstract

The invention relates to the technical field of couplers, in particular to a single-layer microstrip coupler which comprises a main microstrip line and a secondary microstrip line which are mutually coupled, wherein one end of the main microstrip line is configured as an input port of the coupler and is used for receiving electromagnetic wave signals, the other end of the main microstrip line is configured as a through port and is used for outputting signals, one end of the secondary microstrip line is configured as a coupling port of the coupler, the other end of the secondary microstrip line is configured as an isolation port, and triangular hole digging areas are arranged on the non-coupling side of the main microstrip line and the non-coupling side of the secondary microstrip line under the condition that the coupling degree between the main microstrip line and the secondary microstrip line meets the tight coupling degree so as to guide the electromagnetic wave signals to propagate to the through port and the coupling port through the triangular hole digging areas. Through the structural arrangement of the coupler, not only are the high directivity and the tight coupling degree of the single-layer microstrip coupler realized, but also the directivity of the single-layer microstrip coupler can be greatly improved, and the performance of the single-layer microstrip coupler is improved.

Inventors

LI ZEFENG
ZHANG BO
WANG XIAONING
NIU ZHONGQIAN
CHEN NINGBO
FENG YINIAN

Assignees

电子科技大学(深圳)高等研究院
电子科技大学

Dates

Publication Date: 20260508
Application Date: 20260114

Claims (6)

1. A single-layer microstrip coupler is characterized by comprising a main microstrip line and an auxiliary microstrip line which are mutually coupled; one end of the main microstrip line is configured as an input port of a coupler and is used for receiving electromagnetic wave signals, and the other end of the main microstrip line is configured as a through port and is used for outputting signals; one end of the auxiliary microstrip line is configured as a coupling port of the coupler, and the other end is configured as an isolation port; under the condition that the coupling degree between the main microstrip line and the auxiliary microstrip line meets the tight coupling degree, the uncoupled side of the main microstrip line and the uncoupled side of the auxiliary microstrip line are respectively provided with a triangular hole digging area so as to guide the electromagnetic wave signal to propagate to the through port and the coupling port through the triangular hole digging areas; the tight coupling degree condition is that the coupling distance between the main microstrip line and the auxiliary microstrip line is in the range of 1.99 micrometers to 2.01 micrometers; The triangular hole digging areas of the main microstrip line and the triangular hole digging areas of the auxiliary microstrip line are symmetrically distributed along the coupling areas between the main microstrip line and the auxiliary microstrip line; Each triangular hole digging area comprises a plurality of rectangular holes; The rectangular holes are distributed at intervals and are symmetrically distributed along the central line of the triangular hole digging area; the depth of the rectangular holes is sequentially reduced according to the directions of the central lines of the triangular hole digging areas to the ports on the two sides respectively; Rectangular tooth holes are formed in the coupling side of the main microstrip line and the coupling side of the auxiliary microstrip line, the rectangular tooth holes of the main microstrip line and the rectangular tooth holes of the auxiliary microstrip line are symmetrically distributed along the central line of the triangular hole digging area, and the rectangular tooth holes of the main microstrip line and the rectangular tooth holes of the auxiliary microstrip line are staggered.
2. The single layer microstrip coupler according to claim 1, wherein the spacing distance between any adjacent two of said rectangular holes is uniform, and the width of each of said rectangular holes is uniform.
3. The single layer microstrip coupler according to claim 1, wherein said rectangular aperture has a width in the range of 1.99 microns to 2.01 microns.
4. The single-layer microstrip coupler according to any one of claims 1 to 3, further comprising a matching load connected to said isolation port; the matching load is a thin film resistor with a rectangular annular structure, the upper side of the thin film resistor is connected with the isolation port, and a plurality of positions of the thin film resistor are grounded.
5. The single-layer microstrip coupler of claim 4 wherein symmetrical conduction bands are distributed on two sides of said thin film resistor, said conduction bands are provided with symmetrical vias, and said thin film resistor is grounded after being connected to said vias by said conduction bands.
6. The single-layer microstrip coupler according to claim 5, wherein said rectangular slot is disposed non-through said rectangular slot on each microstrip line, said rectangular slot having a depth less than a depth of said rectangular slot.

Description

Single-layer microstrip coupler Technical Field The invention relates to the technical field of couplers, in particular to a single-layer microstrip coupler. Background The directional coupler is used as a key component of a modern communication system such as microwaves, terahertz and the like, and plays an irreplaceable role in the aspects of signal monitoring, power distribution, system calibration, feedback control and the like. With the rapid development of 6G communication, satellite, radar systems and terahertz imaging technologies, the demand for high-performance directional couplers is increasingly urgent, and in particular, higher demands are being made on high integration, miniaturization and high precision. Microstrip structures (i.e., microstrip lines) as a planar transmission line technology exhibit significant advantages over conventional waveguide structures. The microstrip line is composed of a single conductor strip only on a dielectric substrate, has the characteristics of small volume, light weight, wide use band, high reliability, low manufacturing cost and the like, and is particularly suitable for the planarization design and integration of a microwave integrated circuit. Although the microwave loss of the microstrip line is slightly higher than that of the waveguide structure, the planar structure and the semiconductor technology of the microstrip line have high compatibility, so that the microstrip line becomes a preferred transmission line form of modern microwave system design, and more complex circuit functions and higher-density integration can be realized. Existing schemes typically employ multilayer structures or waveguide structures to achieve strong coupling and good directivity of the coupler. However, a coupler of a single-layer microstrip structure (referred to as a single-layer microstrip coupler for short) faces a serious challenge in achieving tight coupling of, for example, 3 dB, 5 dB. On the one hand, the tight coupling degree requires that a larger coupling coefficient is achieved within a limited physical size, while the side coupling mode of the single-layer microstrip structure limits the coupling efficiency. The tight coupling degree means that the coupling distance between two coupled lines is small, and the electromagnetic field control difficulty of the coupling region of the single-layer microstrip structure is remarkably increased at such a small coupling distance. Particularly in the high frequency band, the influence of the dispersion characteristic and the field distribution of the microstrip line on the coupling performance is more complicated. On the other hand, the directivity is to ensure extremely high signal isolation between the coupling port and the isolation port of the coupler, and to avoid the leakage signal mixed into the isolation port in the coupling signal. Insufficient directivity of the coupler will cause the system accuracy to decrease and signal interference to increase, seriously affecting the system performance. Under the condition of tight coupling degree, the coupling distance of the coupler with the single-layer microstrip structure is very small, so that the realization of high directivity becomes very difficult. In addition, when strong coupling is realized, namely, when the coupling pitch is very small, the single-layer microstrip coupler causes rapid deterioration of coupling degree and directivity along with the increase of working frequency and bandwidth. Therefore, the single-layer microstrip coupler has a problem of how to achieve both tight coupling and high directivity. Disclosure of Invention The embodiment of the application solves the technical problems of how to simultaneously realize the tight coupling degree and the high directivity of the single-layer microstrip coupler in the prior art by providing the single-layer microstrip coupler, not only simultaneously realizes the high directivity and the tight coupling degree of the single-layer microstrip coupler, but also greatly improves the directivity of the single-layer microstrip coupler, realizes the high matching performance of a matched load, improves the performance of the single-layer microstrip coupler and other technical effects. In a first aspect, an embodiment of the present invention provides a single-layer microstrip coupler, including a main microstrip line and a sub microstrip line coupled to each other; one end of the main microstrip line is configured as an input port of a coupler and is used for receiving electromagnetic wave signals, and the other end of the main microstrip line is configured as a through port and is used for outputting signals; one end of the auxiliary microstrip line is configured as a coupling port of the coupler, and the other end is configured as an isolation port; And under the condition that the coupling degree between the main microstrip line and the auxiliary microstrip line meets the tight coupling degree, the uncoupled s