CN108736114A - A kind of high clutter reduction cross-coupling band pass filter for S frequency range tuners - Google Patents

Abstract

The invention discloses a kind of high clutter reduction cross-coupling band pass filters for S frequency range tuners, including input feed-in mating end, resonance resonator element, zero compensation unit and output end feed-in mating end, utilize doubling plate printed circuit board microstrip circuit, upper layer is microstrip line, lower layer is full stratum, circuit is microstrip line microwave circuit at the middle and upper levels for it, input signal is input to the input terminal Port1 of input feed-in mating end by 50 ohm microstrips, and input feed-in mating end matches front end input impedance and filter impedance simultaneously；Signal is filtered by resonance resonator element, while zero compensation unit increases the negative feedback of resonance resonator element.The present invention is designed to that totem pattern half-wavelength resonance resonator realizes cross-coupling characteristics, to realize high clutter reduction outside S frequency range proximity band in a manner of particular arrangement using microstrip lines characteristic with position using printed circuit board microstrip circuit.

Description

A High Suppression Clutter Cross-Coupled Bandpass Filter for S-Band LNB

technical field

The invention belongs to the fields of tuner, satellite reception, satellite TV, satellite communication and communication equipment, and in particular relates to a high-suppression clutter cross-coupling bandpass filter for an S-band tuner.

Background technique

With the development of communication technology, the popularization and update of communication systems, especially in densely populated areas, these communication signals are thousands of times stronger than the weak signals received by tuners, and the signals are very close to the receiving frequency band 2520-2670MHz. This is like a nightmare for S-band tuners, and all kinds of filters are born accordingly.

Contents of the invention

The technical problem to be solved by the present invention is to provide a totem type half-wavelength resonant resonator designed by using the microstrip line of the printed circuit board, using the coupling characteristics of the adjacent microstrip lines to realize the cross-coupling characteristics in a specific arrangement and position, in order to realize S-band adjacent out-of-band high rejection clutter A high rejection clutter cross-coupled bandpass filter for S-band tuners.

The present invention is achieved through the following technical solutions: a high-suppression clutter cross-coupled bandpass filter for an S-band tuner, including an input feed-in matching terminal, a resonant resonator unit, a zero point compensation unit and an output terminal Feed into the matching end, use the microstrip line of the double-layer printed circuit board, the upper layer is a microstrip line, the lower layer is a full ground layer, and the upper layer circuit is a microstrip line microwave circuit, and the input signal is input from a 50 ohm microstrip line to the input feed The input terminal Port1 of the matching terminal, the input is fed into the matching terminal to match the input impedance of the front end and the filter impedance at the same time; the signal is filtered by the resonant resonator unit, and the zero point compensation unit increases the negative feedback of the resonant resonator unit; after the signal is filtered, it is fed by the output terminal The input matching end matches the impedance and outputs the signal to the 50 ohm impedance microstrip line through Port2.

As a preferred technical solution, the resonant resonator unit 12 includes six totem-shaped resonators 121, and the resonators are microstrip lines with a total length of about half the wavelength of the center frequency of the passband of the filter.

As a preferred technical solution, the six resonators are resonators No. 1 to No. 6 respectively, and the coupling paths through which the filter mainly transmits signals are resonators 1 to 2, 2 to 3, 3 to 4, 4 to 5, and 5 to 6, and the negative feedback path of the secondary transmission signal is resonator 2 to 5, and 1 to 6. The above-mentioned main transmission coupling path mainly determines the filter pole, and the secondary transmission path mainly determines the zero point.

As a preferred technical solution, the frequency band used is S-band 2520-2670MHz.

As a preferred technical solution, the six totem-type resonators form a six-resonator cross-coupled filter, which includes a signal matching feed-in end, a digital circle resonant resonator, a pole coupling path with a solid line path, and a dotted line path zero coupling path.

As a preferred technical solution, it is a 50-ohm microstrip line input-output system.

The beneficial effects of the present invention are: the present invention utilizes the printed circuit board microstrip line to design a totem-type half-wavelength resonant resonator, utilizes the microstrip line coupling characteristics, and realizes the cross-coupling characteristic with a specific arrangement and position, in order to realize the S-band adjacent band The outer height suppresses clutter.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1: The present invention realizes the microstrip six-resonator cross-coupled filter circuit diagram;

Figure 2: Schematic diagram of the structure of the six-resonator cross-coupled filter realized by the present invention;

Fig. 3: The present invention realizes the simulation characteristic diagram of microstrip six-resonator cross-coupling filter;

Figure 4: Schematic diagram of the structure of the three-resonator cross-coupled filter realized by the present invention;

Fig. 5: The present invention realizes the circuit diagram of the microstrip three-resonator cross-coupling filter;

Fig. 6: The simulated characteristic diagram of the microstrip three-resonator cross-coupling filter realized by the present invention.

Detailed ways

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification (including any appended claims, abstract and drawings), unless expressly stated otherwise, may be replaced by alternative features which are equivalent or serve a similar purpose. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

As shown in Figure 1, the microstrip line of a double-layer printed circuit board is used, the upper layer is a microstrip line, and the lower layer is a full ground layer (full metal layer), and the upper layer circuit is a microstrip line microwave circuit as shown in Figure 1; input The signal is input from a 50-ohm microstrip line to the input port Port1 of the input feeding matching end 11, and the input feeding matching end matches the front-end input impedance and filter impedance at the same time; the signal then passes through the resonant resonator unit 12 (including six resonators) Filtering, at the same time, the zero point compensation unit 13 can increase the negative feedback of the resonant resonator unit, in order to generate additional zero point filtering characteristics, which can increase the suppression of specific frequency bands; after the signal is filtered, it is fed into the matching end 14 from the output end to match the impedance and output the signal through Port2 to 50 ohm impedance microstrip line;

The resonant resonator unit 12 includes six totem-shaped resonators 121. The resonators are microstrip lines with a total length of about half the wavelength (half wavelength) of the center frequency of the passband of the filter, and the peripheral length-to-width ratio can be used according to actual use Variation: Resonance The resonator unit can achieve specific filtering characteristics through different orientations, arrangements, relative distances, and different aspect ratios.

As shown in Figure 2, this schematic diagram is used to briefly supplement the above-mentioned Figure 1, including a signal matching feed-in terminal 21 with a solid line path of arrows, a digital circle resonant resonator 22, and a pole coupling path 23 with a solid line path, and the zero-point coupling path 24 of the dotted line path, and other similarities will not be described; the above-mentioned filter has six resonators, which are No. 1 to No. Resonators 1 to 2, 2 to 3, 3 to 4, 4 to 5, 5 to 6, and the negative feedback path of the secondary transmission signal (the above dotted line path) is resonator 2 to 5, and 1 to 6; the above main The transfer-coupling path primarily determines the filter poles (passband), and the secondary transfer path primarily determines the zeros (out-of-band).

As shown in Figure 3, the curve 31 is the insertion loss (Insert Loss), and the curve 32 is the reflection loss (ReturnLoss); this example is realized by using a double-layer circuit board with a thickness of 20mil model RO4233, and the filter circuit is shown in Figure 1. The circuit size It is 1200x650mil, the passband frequency is 2520～2670MHz, and the out-of-band <2490MHz and >2700MHz have been suppressed by more than 30dB, and the out-of-band frequency is about 1.16% relative to the in-band center frequency.

Another embodiment below illustrates a cross-coupled bandpass filter with three resonators.

As shown in Figure 4, this schematic diagram is similar to the description in Figure 2 above; there are three resonators in the filter, which are resonators 1 to 3, and the coupling path (the above solid line path) for other filters to transmit signals is resonator 1. to 2, 2 to 3, and the negative feedback path of the secondary transfer signal (the dotted line path above) is resonator 2 to 3; the above-mentioned main transfer coupling path mainly determines the filter pole (passband), and the secondary transfer path mainly determines the zero point (out-of-band).

As shown in Figure 5, this example is implemented using a double-layer circuit board with a thickness of 20mil and model RO4233, and the circuit size is 880x400mil; the resonator is a half-wavelength totem-type resonator, and the aspect ratio of each is different due to the characteristic design.

As shown in Figure 6, it is the simulation characteristic of Figure 5 above, where curve 61 is the insertion loss (Insert Loss), and curve 62 is the reflection loss (Return Loss); the passband frequency is 2520-2670MHz, and the out-of-band <2300MHz has been greater than 30dB Above suppression, where the out-of-band frequency is about 8.48% relative to the in-band center frequency.

In the above two examples, in practical applications, the three-resonator filter can be used as the front-end (stage) pre-filter to prevent the front-end of the system from being saturated due to excessive noise. The main reason is that the insertion loss and the size of the six-resonator filter are small. As the main filter, the out-of-band rejection is relatively large, but the insertion loss is also relatively large; although the above examples only have three and six resonator combined filters, in practical applications, 2 to N resonators can be designed according to requirements. Through different appearance characteristics such as different directions, arrangements, relative distances, and different lengths and widths, and adding additional zero point compensation at appropriate positions, the filtering characteristics of specific requirements can be achieved.

The above is only a specific implementation of the present invention, but the scope of protection of the present invention is not limited thereto, and any changes or replacements that do not come to mind through creative work shall be covered within the scope of protection of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope defined in the claims.

Claims (6)

1. A high-suppression clutter cross-coupled bandpass filter for an S-band tuner is characterized in that: it includes an input feed-in matching end, a resonant resonator unit, a zero compensation unit and an output feed-in matching end, The microstrip line of the double-layer printed circuit board is used, the upper layer is a microstrip line, and the lower layer is a full ground layer. The upper layer circuit is a microstrip line microwave circuit, and the input signal is input from a 50-ohm microstrip line to the input terminal Port1 of the input feed-in matching terminal. ,The input is fed into the matching end to match the front-end input impedance and filter impedance at the same time; the signal is filtered by the resonant resonator unit, and the zero point compensation unit increases the negative feedback of the resonant resonator unit; after the signal is filtered, it is fed into the matching end by the output end to match the impedance Output signal to 50 ohm impedance microstrip line via Port2. 2. A kind of high suppression clutter cross-coupled bandpass filter for S band tuner as claimed in claim 1, is characterized in that: described resonant resonator unit 12 is to comprise six totem type resonators 121 , the resonator is a microstrip line with a total length of about half the wavelength of the central frequency of the passband of the filter. 3. A kind of high suppression clutter cross-coupled bandpass filter for S-band tuner as claimed in claim 2, characterized in that: the six resonators are respectively No. 1 to No. 6 resonators, wherein The coupling path of the filter's main signal transmission is resonator 1 to 2, 2 to 3, 3 to 4, 4 to 5, 5 to 6, and the negative feedback path of the secondary transmission signal is resonator 2 to 5, and 1 To 6, the above-mentioned main transmission coupling path mainly determines the filter pole, and the secondary transmission path mainly determines the zero point. 4. A high clutter suppression cross-coupled bandpass filter for an S-band tuner as claimed in claim 1, characterized in that: the frequency band used is S-band 2520-2670 MHz. 5. A kind of high suppression clutter cross-coupling bandpass filter for S-band tuner as claimed in claim 2, characterized in that: said six totem-type resonators form a six-resonator cross-coupling filter The device includes a signal matching feed-in terminal, a digital circle resonant resonator, a pole coupling path with a solid line path, and a zero point coupling path with a dotted line path. 6. A high-suppression clutter cross-coupled bandpass filter for an S-band tuner as claimed in claim 1, characterized in that it is a 50-ohm microstrip line I/O system.