CN217957046U - Filter circuit for half-duplex transmitter - Google Patents
Filter circuit for half-duplex transmitter Download PDFInfo
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- CN217957046U CN217957046U CN202221988232.9U CN202221988232U CN217957046U CN 217957046 U CN217957046 U CN 217957046U CN 202221988232 U CN202221988232 U CN 202221988232U CN 217957046 U CN217957046 U CN 217957046U
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Abstract
The utility model discloses a filter circuit for a half-duplex transmitter, which comprises a first port, a first capacitor, a first inductor, a second capacitor, a second inductor, a third capacitor and a second port; a first capacitor, a first polar plate of which is connected with the first port, and a second polar plate of which is grounded; one end of the first inductor is connected with the first port, and the other end of the first inductor is connected with the first pole plate of the second capacitor; a second capacitor, the second plate of which is grounded; one end of the second inductor is connected with the first pole plate of the second capacitor, and the other end of the second inductor is connected with the second port; a third capacitor, the first polar plate of which is connected with the second port and the second polar plate of which is grounded; the first port receives a radio frequency signal, and the radio frequency signal is sequentially filtered by a first capacitor, a first inductor, a second capacitor, a second inductor and a third capacitor to obtain a target radio frequency signal and is output by a second port; the problems of complex filter circuit structure, high circuit design cost and the like of the half-duplex transmitter are solved.
Description
Technical Field
The utility model relates to an integrated circuit technology field, concretely relates to a filter circuit for half-duplex transmitter.
Background
Filter circuits are generally classified into two broad categories, passive filtering and active filtering. If the filter circuit element is composed of only passive elements (resistors, capacitors, inductors), the filter circuit element is called a passive filter circuit. The main forms of passive filtering are capacitive filtering, inductive filtering and complex filtering (including inverted-L filtering, LC pi-type filtering, RC pi-type filtering and the like). A filter circuit is called an active filter circuit if it is composed of not only passive elements but also active elements (bipolar type tubes, unipolar type tubes, integrated operational amplifiers). The main form of active filtering is active RC filtering, also called electronic filter. In the existing filter circuit, one circuit can realize both high-pass filtering and low-pass filtering, but the structure is complex, which is not beneficial to the integration of a 3GPP Long Term Evolution (LTE) half-duplex transmitter communication circuit, and if a surface acoustic wave filter or a low-temperature co-fired ceramic filter is directly used for replacement, the circuit design cost is increased.
SUMMERY OF THE UTILITY MODEL
In view of the above shortcomings in the prior art, an object of the present invention is to provide a filter circuit for a half-duplex transmitter, which is used for solving the problems of complex structure and high cost of circuit design of the filter circuit of the half-duplex transmitter in the prior art.
To achieve the above and other related objects, the present invention provides a filter circuit for a half-duplex transmitter, including a first port, a first capacitor, a first inductor, a second capacitor, a second inductor, a third capacitor and a second port;
a first capacitor, a first polar plate of which is connected with the first port, and a second polar plate of which is grounded;
one end of the first inductor is connected with the first port, and the other end of the first inductor is connected with the first polar plate of the second capacitor;
a second capacitor, the second plate of which is grounded;
one end of the second inductor is connected with the first polar plate of the second capacitor, and the other end of the second inductor is connected with the second port;
a third capacitor, wherein a first polar plate of the third capacitor is connected with the second port, and a second polar plate of the third capacitor is grounded;
the first port receives a radio frequency signal output by a power amplifier of a half-duplex transmitter, and the radio frequency signal is sequentially filtered by the first capacitor, the first inductor, the second capacitor, the second inductor and the third capacitor to obtain a target radio frequency signal and is output by the second port.
In an embodiment of the present invention, the filter circuit for the half-duplex transmitter further includes a zero ohm resistor, one end of the zero ohm resistor is connected to the first pole plate of the third capacitor, the other end of the zero ohm resistor is connected to the second port, the first pole plate of the third capacitor passes through the zero ohm resistor and the second port, the other end of the second inductor passes through the zero ohm resistor and the second port, the rf signal passes through the first capacitor, the first inductor, the second capacitor, the second inductor and the third capacitor are sequentially filtered, and then the target rf signal is obtained and sequentially passes through the zero ohm resistor and the second port is output.
In an embodiment of the invention, the zero ohm resistor includes a third inductor or a fourth capacitor.
In an embodiment of the present invention, the package size of the zero ohm resistor, the package size of the first capacitor, the package size of the second capacitor, the package size of the third capacitor, the package size of the first inductor, and the package size of the second inductor are all equal.
In an embodiment of the present invention, the package size of the zero ohm resistor, the package size of the first capacitor, the package size of the second capacitor, the package size of the third capacitor, the package size of the first inductor, and the package size of the second inductor all include 0201.
In an embodiment of the present invention, the inductance of the first inductor and the inductance of the second inductor are both less than 22nh.
In an embodiment of the present invention, the inductance value range of the first inductor and the inductance value range of the second inductor both include 10nh-18nh.
In an embodiment of the present invention, the capacitance of the first capacitor, the capacitance of the second capacitor and the capacitance of the third capacitor are all less than 10pF.
In an embodiment of the present invention, the capacitance range of the first capacitor, the capacitance range of the second capacitor and the capacitance range of the third capacitor include 1-4pF.
In an embodiment of the present invention, the half-duplex transmitter includes an LTE half-duplex transmitter.
The utility model provides a filter circuit for a half-duplex transmitter, which comprises a first port, a first capacitor, a first inductor, a second capacitor, a second inductor, a third capacitor and a second port; a first capacitor, a first polar plate of which is connected with the first port, and a second polar plate of which is grounded; one end of the first inductor is connected with the first port, and the other end of the first inductor is connected with the first pole plate of the second capacitor; a second capacitor, the second plate of which is grounded; one end of the second inductor is connected with the first polar plate of the second capacitor, and the other end of the second inductor is connected with the second port; a third capacitor, the first polar plate of which is connected with the second port and the second polar plate of which is grounded; the first port receives a radio frequency signal, and the radio frequency signal is sequentially filtered by a first capacitor, a first inductor, a second capacitor, a second inductor and a third capacitor to obtain a target radio frequency signal and is output by a second port; the problems that in the prior art, a filter circuit of a half-duplex transmitter is complex in structure, high in circuit design cost and the like are solved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:
fig. 1 is a schematic diagram of a filter circuit for a half-duplex transmitter according to an exemplary embodiment of the present application;
fig. 2 is another schematic diagram of a filtering circuit for a half-duplex transmitter according to an exemplary embodiment of the present application;
FIG. 3 is a graph of parameters at a frequency of 3.4GHz as shown in an exemplary embodiment of the present application;
FIG. 4 is a graph of parameters at a frequency of 5.1GHz as shown in an exemplary embodiment of the present application.
Detailed Description
The embodiments of the present invention will be described with reference to the accompanying drawings and preferred embodiments, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure in the specification. The present invention can be implemented or applied by other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are presented for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Referring to fig. 1-4, it should be noted that the drawings provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and only the components related to the present invention are shown in the drawings rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, number and proportion of the components in actual implementation may be changed at will, and the layout of the components may be more complicated.
In the following description, numerous details are set forth to provide a more thorough explanation of embodiments of the present invention, however, it will be apparent to one skilled in the art that embodiments of the present invention may be practiced without these specific details, and in other embodiments, well-known structures and devices are shown in block diagram form rather than in detail in order to avoid obscuring embodiments of the present invention.
Referring to fig. 1, the present invention provides a filter circuit for a half-duplex transmitter, including a first port 1, a first capacitor C1, a first inductor L1, a second capacitor C2, a second inductor L2, a third capacitor C3, and a second port 2; a first plate of the first capacitor C1 is connected to the first port 1, and a second plate thereof is grounded; one end of the first inductor L1 is connected to the first port 1, and the other end thereof is connected to the first plate of the second capacitor C2; a second capacitor C2, the second plate of which is grounded; one end of the second inductor L2 is connected to the first plate of the second capacitor C2, and the other end thereof is connected to the second port 2; a third capacitor C3, a first plate of which is connected to the second port 2 and a second plate of which is grounded; the first port 1 receives radio frequency signals, and the radio frequency signals are sequentially filtered by a first capacitor C1, a first inductor L1, a second capacitor C2, a second inductor L2 and a third capacitor C3 to obtain target radio frequency signals and are output by a second port 2; the problems that in the prior art, the filter circuit structure of a half-duplex transmitter is complex, the circuit design cost is high and the like are solved.
Referring to fig. 2, a filter circuit for a half-duplex transmitter includes a first port 1, a first capacitor C1, a first inductor L1, a second capacitor C2, a second inductor L2, a third capacitor C3, a zero ohm resistor R1, and a second port 2; a first plate of the first capacitor C1 is connected to the first port 1, and a second plate thereof is grounded; a first inductor L1, one end of which is connected to the first port 1 and the other end of which is connected to the first plate of the second capacitor C2; a second capacitor C2, the second plate of which is grounded; a second inductor L2, one end of which is connected to the first plate of the second capacitor C2, and the other end of which is connected to one end of the zero ohm resistor R1 and the first plate of the third capacitor C3, respectively; a third capacitor C3, a second plate of which is grounded; the other end of the zero ohm resistor R1 is connected with the second port 2; the first port 1 receives radio frequency signals, and the radio frequency signals are sequentially filtered by the first capacitor C1, the first inductor L1, the second capacitor C2, the second inductor L2 and the third capacitor C3 to obtain target radio frequency signals, and the target radio frequency signals are sequentially output through the zero ohm resistor R1 and the second port 2.
In an embodiment, the half-duplex transmitter comprises an LTE (3 GPP Long Term Evolution) half-duplex transmitter. After a radio frequency signal comes out of a PA _ out end of a transmitter power amplifier, the radio frequency signal enters from a first port and flows through a first capacitor C1, the first capacitor C1 is a parallel capacitor, the radio frequency signal passes through the parallel capacitor C1, the first capacitor C1 is grounded and filters a part of high-frequency signal and then reaches a first inductor L1, the first inductor L1 is a series inductor, the high-frequency signal is filtered and consumed again, the signal passes through a second capacitor C2, the second capacitor C2 is a parallel capacitor, the second capacitor C2 is grounded and then carries out high-frequency signal filtering again, the signal enters a second inductor L2, the second inductor L2 is a series inductor, the series inductor L2 carries out consumption filtering again on the high-frequency signal, the signal flows through a third capacitor C3, the third capacitor C3 is a parallel capacitor, the third capacitor C3 is grounded, the high-frequency signal flows through a first resistor R1 after being subjected to preset with a resistance of 0R, the resistance can be subjected to final filtering according to an actual test condition, the later stage, namely the high-frequency signal can be flexibly treated by a parallel capacitor or the third capacitor, the effect of the fourth capacitor is changed to be treated by a fourth capacitor, and the high-frequency inductor L2 is subjected to be treated by the high-level inductor. In general, 0R can be attached to R1 to satisfy suppression of higher harmonic components. The reservation of R1 is mainly to increase the better compatibility and filtering capability of the circuit.
In one embodiment, the package size of the zero ohm resistor, the package size of the first capacitor, the package size of the second capacitor, the package size of the third capacitor, the package size of the first inductor and the package size of the second inductor are all equal; for example, the package size of the zero ohm resistor, the package size of the first capacitor, the package size of the second capacitor, the package size of the third capacitor, the package size of the first inductor, and the package size of the second inductor may all be 0201.
In one embodiment, the inductance of the first inductor and the inductance of the second inductor are both less than 22nh. Specifically, the inductance value range of the first inductor and the inductance value range of the second inductor each include 10nh-18nh. For example, it may be 10nh, 11nh, 12nh, 13nh, 14nh, 15nh, 16nh, 17nh, 18nh, or the like.
In one embodiment, the capacitance values of the first capacitor, the second capacitor and the third capacitor are all less than 10pF. Specifically, the capacitance value range of the first capacitor, the capacitance value range of the second capacitor and the capacitance value range of the third capacitor comprise 1pF-4pF. For example, it may be 1pF, 1.1pF, 1.2pF, 1.3pF, 1.4pF, 1.5pF, 2pF, 2.5pF, 2.7pF, 2.8pF, 2.9pF, 3pF, 3.5pF, 4pF, etc.
In one embodiment, the filter circuit for the half-duplex transmitter mainly aims at the applicable frequency of 1700MHz-2200MHz, the second harmonic component of the LTE intermediate frequency communication band is mainly concentrated in 3400MHz to 4400MHz, and the third harmonic component is mainly concentrated in 5100MHz to 6600MHz, and in practical production application, the suppression of the second harmonic component generated in the transmitter is one of the most troublesome problems. In this embodiment, simulation software RFSIM simulation finds that the S11 parameter (input return loss) at 3400MHz can reach 0.01db, the S21 parameter (forward transmission coefficient) can reach 24.73dB, and the specific numerical curve is shown in fig. 3. The S11 parameter at 5100MHz is 143.8udB, the parameter of S21 is 44.8dB, and the specific numerical curve is detailed in figure 4. Wherein the abscissa of fig. 3 and the abscissa of fig. 4 are both frequencies, and the ordinate of fig. 3 and the ordinate of fig. 4 are both decibels. Therefore, the second and third harmonic components can be perfectly inhibited in the working frequency range of 1700MHz-2200MHz in the embodiment. The 1608-packaged LTCC filter having a passband of 1700MHz to 2200MHz under the same conditions has an S11 parameter of 0.01db at 3.4GHz, an S21 parameter of 43.39db at 5.1GHz, an S11 parameter of 0.01db at 5.1GHz, and an S21 parameter of 48.6db. In general, a filter can completely satisfy the requirement of harmonic suppression as long as the filter can attenuate by about 25 db. Therefore, the embodiment can completely meet the requirement of harmonic suppression in the LTE half-duplex transmitter circuit with the working frequency band of 1700MHz-2200 MHz.
Claims (10)
1. A filter circuit for a half-duplex transmitter is characterized by comprising a first port, a first capacitor, a first inductor, a second capacitor, a second inductor, a third capacitor and a second port;
a first capacitor, a first polar plate of which is connected with the first port, and a second polar plate of which is grounded;
one end of the first inductor is connected with the first port, and the other end of the first inductor is connected with the first pole plate of the second capacitor;
a second capacitor, the second plate of which is grounded;
one end of the second inductor is connected with the first polar plate of the second capacitor, and the other end of the second inductor is connected with the second port;
a third capacitor, wherein the first pole plate of the third capacitor is connected with the second port, and the second pole plate of the third capacitor is grounded;
the first port receives a radio frequency signal output by a power amplifier of a half-duplex transmitter, and the radio frequency signal is sequentially filtered by the first capacitor, the first inductor, the second capacitor, the second inductor and the third capacitor to obtain a target radio frequency signal and is output by the second port.
2. The filter circuit for a half-duplex transmitter according to claim 1, wherein the filter circuit for a half-duplex transmitter further includes a zero ohm resistor, one end of the zero ohm resistor is connected to the first plate of the third capacitor, the other end of the zero ohm resistor is connected to the second port, the first plate of the third capacitor is connected to the second port through the zero ohm resistor, the other end of the second inductor is connected to the second port through the zero ohm resistor, and the rf signal is filtered sequentially through the first capacitor, the first inductor, the second capacitor, the second inductor, and the third capacitor to obtain a target rf signal and is output sequentially through the zero ohm resistor and the second port.
3. The filter circuit for a half-duplex transmitter of claim 2, wherein the zero ohm resistor comprises a third inductor or a fourth capacitor.
4. The filter circuit for a half-duplex transmitter of claim 2, wherein a package size of the zero ohm resistor, a package size of the first capacitor, a package size of the second capacitor, a package size of the third capacitor, a package size of the first inductor, and a package size of the second inductor are all equal.
5. The filter circuit for a half-duplex transmitter of claim 4, wherein the package size of the zero ohm resistor, the package size of the first capacitor, the package size of the second capacitor, the package size of the third capacitor, the package size of the first inductor, and the package size of the second inductor all comprise 0201.
6. The filter circuit for a half-duplex transmitter of claim 1, wherein the inductance value of the first inductor and the inductance value of the second inductor are both less than 22nh.
7. The filter circuit for a half-duplex transmitter of claim 6, wherein the range of inductance values of the first inductor and the range of inductance values of the second inductor each comprise 10nh-18nh.
8. The filter circuit for a half-duplex transmitter of claim 1, wherein the capacitance value of the first capacitor, the capacitance value of the second capacitor, and the capacitance value of the third capacitor are each less than 10pF.
9. The filter circuit for a half-duplex transmitter of claim 8, wherein the range of capacitance values of the first capacitor, the range of capacitance values of the second capacitor, and the range of capacitance values of the third capacitor comprise 1pF-4pF.
10. The filtering circuit for a half-duplex transmitter according to claim 1, wherein the half-duplex transmitter comprises an LTE half-duplex transmitter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221988232.9U CN217957046U (en) | 2022-07-29 | 2022-07-29 | Filter circuit for half-duplex transmitter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221988232.9U CN217957046U (en) | 2022-07-29 | 2022-07-29 | Filter circuit for half-duplex transmitter |
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| CN217957046U true CN217957046U (en) | 2022-12-02 |
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| CN202221988232.9U Active CN217957046U (en) | 2022-07-29 | 2022-07-29 | Filter circuit for half-duplex transmitter |
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