CN114204235A

CN114204235A - Monoblock filter

Info

Publication number: CN114204235A
Application number: CN202111532635.2A
Authority: CN
Inventors: 高红; 杨世朝; 高中有
Original assignee: Sichuan Tianyi Comheart Telecom Co Ltd
Current assignee: Sichuan Tianyi Comheart Telecom Co Ltd
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2022-03-18

Abstract

The invention discloses a monoblock filter, which comprises: the resonant cavity comprises a ceramic substrate and a metal layer positioned on one end face of the ceramic substrate, wherein the metal layer is provided with a metallization pattern, the ceramic substrate is provided with a metallization via hole penetrating through the ceramic substrate, the metal layer is used for adjusting frequency and coupling between cavities, and the electromagnetic field distribution of coupling between adjacent resonant cavities is an even mode state in which a magnetic field is in a leading state or an odd mode state in which the electric field coupling is in a leading state. The invention provides a monoblock filter which is suitable for 5G RRU radio frequency pass filtering, the coupling is the mixed coupling of electricity and magnetism, the electricity or magnetism coupling can be flexibly used through the design of end face patterns in actual use, the required zero point is generated and controlled, and the suppression requirement of a complex filter is met.

Description

Monoblock filter

Technical Field

The invention relates to the technical field of filters, in particular to a monoblock filter.

Background

The radio frequency front end is a core component in mobile communication equipment, and the subdivision components of the radio frequency front end comprise: filters (Filter), Power Amplifiers (PA), radio frequency switches (Switch), Low Noise Amplifiers (LNA), antenna tuners, etc., of which filters are an important part. The 5G radio frequency front-end filter product mainly develops towards three targets of low power consumption, low cost and high performance.

The GSM-R superconducting radio frequency front-end high-temperature superconducting filter is applied to a GSM-R private network base station of a Chinese railway, and is made of a high-temperature superconducting thin film material, the order of the GSM-R superconducting radio frequency front-end high-temperature superconducting filter is 6-20 orders, the circuit structure of the GSM-R superconducting radio frequency front-end high-temperature superconducting filter comprises a plurality of parallel loops for simulating oscillator distribution parameters and transmission lines for simulating coupling coefficients among oscillators, each section of the transmission lines are sequentially connected in series, the transmission line at the initial end and the transmission line at the tail end are respectively connected with ports for simulating source impedance and load impedance, nodes between adjacent transmission lines are connected with one parallel loop, and the parallel loop is formed by connecting a resistor, an inductor and a capacitor in parallel; the micro-strip structure of the GSM-R superconducting radio frequency front-end high-temperature superconducting filter comprises a plurality of vibrators which are arranged in a comb shape at a certain interval, and the vibrators are formed by bending micro-strip lines. However, the structure is too complex and is not suitable for the front-end filtering of the radio frequency of the small cell RRU.

A filter is a frequency-selective device that passes certain frequency components of a signal while significantly attenuating other frequency components. By using the frequency selection function of the filter, interference noise can be filtered out or spectrum analysis can be carried out. In other words, any device or system that can pass a specific frequency component of a signal and greatly attenuate or suppress other frequency components is called a filter. The filter is a device for filtering waves. "wave" is a very broad physical concept, and in the field of electronics, is narrowly limited to refer specifically to processes that describe the variation of values of various physical quantities over time. This process is converted into a time function of voltage or current, called time waveform of various physical quantities, or called signal, by the action of various sensors. Since the argument time is continuously valued, it is called a continuous time Signal, which is also conventionally called an Analog Signal (Analog Signal).

Filtering is an important concept in signal processing, and a filter circuit in a direct current stabilized power supply has the functions of reducing alternating current components in pulsating direct current voltage as much as possible, keeping the direct current components, reducing the ripple coefficient of output voltage and smoothing the waveform.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a monoblock filter for solving the technical problem that the filter in the prior art cannot meet the filtering requirement of a front radio frequency end of a small cell RRU.

The purpose of the invention is realized by the following technical scheme:

a monoblock filter, comprising: the resonant cavity comprises a ceramic matrix and a metal layer located on one end face of the ceramic matrix, wherein the metal layer is provided with a metallization pattern, the ceramic matrix is provided with a metallization via hole penetrating through the ceramic matrix, and the metal layer is used for adjusting frequency and coupling between cavities.

Furthermore, the number of the resonant cavities is 6.

Further, the monoblock filter has three transmission zeros.

Furthermore, the distribution of the coupled electromagnetic field between adjacent resonant cavities is an even mode state in which the magnetic field is in a dominant state or an odd mode state in which the electric field coupling is in a dominant state.

Furthermore, a thin metal strip is adopted to generate cross coupling between non-adjacent resonant cavities, so as to realize transmission zero.

Furthermore, if the cross coupling is positive, a positive transmission zero point is generated, and the transmission zero point is positioned on the right side of the passband; if the cross-coupling is negative, a negative transmission zero is generated, which is located on the left side of the passband.

The invention has the beneficial effects that:

(1) the monoblock filter is suitable for 5G RRU radio frequency pass filtering;

(2) the invention can meet the filtering of 5G radio frequency front-end signals, and can achieve the filtering of other frequency band signals through structural extension;

(3) the filter has a simple structure, the coupling is the mixed coupling of electricity and magnetism, and the electric or magnetic coupling can be flexibly used through the design of end face patterns in actual use to generate and control required zero points and meet the suppression requirement of a complex filter;

(4) the invention generates proper electromagnetic field distribution to meet the signal condition required by generating transmission zero in the circuit model by controlling the coupling structure of the filter, and can be expanded to the transmission zero of filters in other frequency bands.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic diagram of a resonant cavity structure of the present invention;

FIG. 3 is a schematic end view of a resonant cavity according to the present invention;

FIG. 4 is a schematic diagram of a filter transmission path;

FIG. 5 is a graph of magnetic field distribution around a metallized via;

FIG. 6 is a graph of the electric field distribution around the end pattern;

FIG. 7 is a magnetic field distribution diagram for an even mode condition;

FIG. 8 is an electric field distribution diagram for an even mode condition;

FIG. 9 is an odd mode state magnetic field distribution plot;

FIG. 10 is an odd mode electric field distribution diagram;

FIG. 11 is a schematic diagram of a six-cavity triple-zero filter simulation;

FIG. 12 is a schematic diagram of the creation of a transmission zero at the low end of the passband;

fig. 13 is a schematic diagram of generating a transmission zero at the high end of the pass band.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to clearly understand the technical features, objects and effects of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the present embodiment, as shown in fig. 1, fig. 2, fig. 3, and fig. 11, a monoblock filter includes: the resonant cavity comprises a ceramic matrix and a metal layer located on one end face of the ceramic matrix, wherein the metal layer is provided with a metallization pattern, the ceramic matrix is provided with a metallization via hole penetrating through the ceramic matrix, and the metal layer is used for adjusting frequency and coupling between cavities.

In this embodiment, the number of the resonant cavities is 6.

In this embodiment, the monoblock filter has three transmission zeros.

In this embodiment, the electromagnetic field distribution of the coupling between adjacent resonators is an even mode state in which the magnetic field is in a dominant state or an odd mode state in which the electric field coupling is in a dominant state.

In this embodiment, a thin metal strip is used to generate cross coupling between non-adjacent resonators for implementing transmission zero.

In this embodiment, in order to realize the transmission zero point, it is necessary to generate coupling between non-adjacent resonators, which is called cross coupling. With respect to the main coupling between adjacent resonators, if the cross coupling is positive, a positive transmission zero (located on the right of the passband) can be generated; if the cross-coupling is negative, a negative transmission zero (located to the left of the passband) can be generated.

Specifically, as shown in fig. 1, a monoblock filter includes a signal input port, a resonator, a cross-coupling, and a signal output port.

The number of the signal input ports is 1, the number of the resonant cavities is 6, and the number of the output ports is 1;

in order to achieve transmission zeros, coupling must occur between non-adjacent resonators, referred to as cross-coupling. With respect to the main coupling between adjacent resonators, if the cross coupling is positive, a positive transmission zero (located on the right of the passband) can be generated; if the cross-coupling is negative, a negative transmission zero (located to the left of the passband) can be generated.

As shown in fig. 4, there are two signal transmission paths, and path 1 is: 1-3; the path 2 is: 1-2-3. when the signals of the two paths meet the appropriate conditions, equal amplitude and opposite phase signals are satisfied at a certain frequency point (or points) inside the common cavity. A transmission zero is obtained at this time. By controlling the coupling structure of the filter, an appropriate electromagnetic field distribution is generated to meet the signal condition required by generating a transmission zero point in the circuit model.

Fig. 5 and 6 show the field distribution, with a predominant magnetic field distribution around the metallized via and a predominant electric field distribution around the endface pattern.

As shown in fig. 7 to 10, the electromagnetic field distribution of coupling between adjacent resonators may be an even mode state in which the magnetic field is in a dominant state; or an odd mode state where the electric field coupling is in a dominant state.

The odd-even mode distinguishing method structurally finds a symmetrical plane, if the electric field distribution is symmetrical about the plane, the even mode is found, and if not, the odd mode is found.

Realization of transmission zero point

A thin metal strip is used to generate the coupling between the resonator 1 and the resonator 3, the two coupling paths being 1-2-3 and 1-3, respectively.

Source-load cross-coupling implementation

Sometimes, due to the requirement of product index and the limitation of structure, the transmission zero point must be realized by using the source and the load to participate in cross coupling.

Fig. 11 is a schematic diagram of a 6-cavity, 3-zero filter simulation. Where S-2 and 5-L produce the right two transmission zeroes and 2-3 the left transmission zero.

In FIG. 12, the primary coupling is S-1-2, where S-1 is dominated by electrical coupling, 1-2 is dominated by electrical coupling, and the cross-coupling is S-2, dominated by electrical coupling. The electric fields generated on the resonator 2 by the two signals are opposite, the cross coupling is negative coupling, and a transmission zero point can be generated at the low end of the passband.

In FIG. 13, the primary coupling is S-1-2, where S-1 is dominated by electrical coupling, 1-2 is dominated by magnetic coupling, and the cross-coupling is S-2, dominated by electrical coupling. The electric fields generated by the two paths of signals on the resonator 2 are the same, the cross coupling is positive coupling, and a transmission zero point can be generated at the high end of the passband.

The invention has the beneficial effects that: the invention provides a monoblock filter which is suitable for 5G RRU radio frequency pass filtering.

(1) The invention can meet the filtering of 5G radio frequency front-end signals, and can achieve the filtering of other frequency band signals through structural extension;

(2) the filter has a simple structure, the coupling is the mixed coupling of electricity and magnetism, and the electric or magnetic coupling can be flexibly used through the design of end face patterns in actual use to generate and control required zero points and meet the suppression requirement of a complex filter;

(3) the invention generates proper electromagnetic field distribution to meet the signal condition required by generating transmission zero point in the circuit model by controlling the coupling structure of the filter. And can be extended to the transmission zero of other frequency band filters.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A monoblock filter, comprising: the resonant cavity comprises a ceramic matrix and a metal layer located on one end face of the ceramic matrix, wherein the metal layer is provided with a metallization pattern, the ceramic matrix is provided with a metallization via hole penetrating through the ceramic matrix, and the metal layer is used for adjusting frequency and coupling between cavities.

2. The monoblock filter according to claim 1, wherein the number of the resonant cavities is 6.

3. A monoblock filter according to claim 1, characterized in that it has three transmission zeros.

4. The monoblock filter of claim 1, wherein the distribution of the coupled electromagnetic field between adjacent resonators is an even mode state in which the magnetic field is in a dominant state or an odd mode state in which the electric field coupling is in a dominant state.

5. A monoblock filter according to claim 1 wherein a thin metal strip is used to cross-couple non-adjacent resonators for transmission zeros.

6. A monoblock filter according to claim 5, wherein if the cross-coupling is positive, a positive transmission zero is generated, the transmission zero being located to the right of the pass band; if the cross-coupling is negative, a negative transmission zero is generated, which is located on the left side of the passband.