CN113242028A - On-chip integrated radio frequency band-pass filter circuit - Google Patents
On-chip integrated radio frequency band-pass filter circuit Download PDFInfo
- Publication number
- CN113242028A CN113242028A CN202110344216.XA CN202110344216A CN113242028A CN 113242028 A CN113242028 A CN 113242028A CN 202110344216 A CN202110344216 A CN 202110344216A CN 113242028 A CN113242028 A CN 113242028A
- Authority
- CN
- China
- Prior art keywords
- switch group
- parallel
- band
- pass filter
- chip integrated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/12—Bandpass or bandstop filters with adjustable bandwidth and fixed centre frequency
Landscapes
- Filters And Equalizers (AREA)
Abstract
The invention discloses an on-chip integrated radio frequency band-pass filter circuit, and relates to the technical field of filters. The first switch group and the second switch group are respectively composed of switches P1, P2, P3 and P4; the first switch groups P1, P2, P3 and P4 are connected in parallel and are connected with the respective transimpedance amplifiers; the input impedance Zin is connected with the first switch group and the second switch group; the P2 of the second switch group is connected with the P1 of the first switch group in parallel; the P1 of the second switch group is connected with the P2 of the first switch group in parallel; the P4 of the second switch group is connected with the P3 of the first switch group in parallel; the P3 of the second switch group is connected with the P4 of the first switch group in parallel; capacitances are provided between P1 and P2 and P3 and P4. The radio frequency band-pass filter circuit provided by the invention can be used for solving the problem that band-pass filtering is not sharp enough and improving the inhibition of the existing band-pass filtering on out-of-band interference.
Description
Technical Field
The invention relates to the technical field of filters, in particular to an on-chip integrated radio frequency band-pass filter circuit.
Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasting, etc., such a generally multiple access network supports communication for multiple users by sharing available network resources, a wireless communication network may include multiple base stations supporting communication for multiple mobile stations, the mobile stations may communicate with the base stations via downlink and uplink, the mobile stations and/or the base stations may include any of various suitable types of filters, such as N-channel filters, which have other applications besides wireless communication, existing band-pass filtering is not sharp enough, and the existing band-pass filtering has yet to be improved in its rejection of out-of-band interference, and to this end, an on-chip integrated radio frequency band-pass filtering circuit is proposed to solve the above-mentioned problems.
Disclosure of Invention
In view of the deficiencies of the prior art, the present invention provides an on-chip integrated rf bandpass filter circuit to solve the problems set forth in the background art.
In order to achieve the purpose, the invention provides the following technical scheme: an on-chip integrated radio frequency band-pass filter circuit mainly comprises switches P1, P2, P3 and P4, a capacitor and an inductor;
wherein, the first switch group and the second switch group are respectively composed of switches P1, P2, P3 and P4; the first switch groups P1, P2, P3 and P4 are connected in parallel and are connected with the respective transimpedance amplifiers; the input impedance Zin is connected with the first switch group and the second switch group; the P2 of the second switch group is connected with the P1 of the first switch group in parallel; the P1 of the second switch group is connected with the P2 of the first switch group in parallel; the P4 of the second switch group is connected with the P3 of the first switch group in parallel; the P3 of the second switch group is connected in parallel with the P4 of the first switch group, and the capacitors are arranged between the P1 and the P2 and between the P3 and the P4. Further optimizing the technical scheme, the circuit structure of the 4-Phase N-path Filter is realized by a 25% duty ratio quadrature passive mixer, wherein ZBB is a load of an analog baseband (BB) and is equivalent to parallel impedance of a resistor RBB and a capacitor CBB.
According to the technical scheme, the input impedance characteristic of the 4-Phase N-path Filter is further optimized, and simulation shows that the frequency response of the input impedance characteristic is automatically tuned along with the local oscillation frequency, so that a relatively sharp band-pass filtering characteristic can be realized near the local oscillation frequency.
According to the technical scheme, due to the intercommunication characteristic of the RF end and the BB end of the passive mixer, almost no isolation exists, when an RF signal is down-converted to the BB end, the RF signal can be shaped and filtered by the impedance of the BB end, then the shaped BB signal is up-converted by the passive mixer and fed through to the RF end, the impedance characteristic of the BB end is moved to the local oscillation frequency by the up-converted signal, and therefore the high-Q-value band-pass filtering characteristic of the radio frequency end is formed.
Further optimising the solution, in some aspects the amplifier circuit may comprise a degeneration circuit for stability and/or a polyphase feedback circuit for reducing in-band peaks.
Further optimizing the technical scheme, in order to further promote the suppression of the out-of-band interference, the Passive Mixer in the N-path Filter can be realized as a Dual Mixer structure.
Further optimizing the technical scheme that C is arranged at the frequency of TX LeakageMIXCan be seen as a short circuit, so the input impedance of the NPF is at ω TX1/2, which is a further reduction of the impedance of a Mixer switch, becomesR SW,NP And 2, further improving the filtering of the output end of the LNA to the TX Blocker.
Compared with the prior art, the invention provides an on-chip integrated radio frequency band-pass filter circuit, which has the following beneficial effects:
the radio frequency band-pass Filter circuit integrated on the chip adopts a structure called N-path Filter (NPF) to realize a required band-pass Filter, solves the problem that the existing band-pass Filter is not sharp enough, and improves the inhibition of the existing band-pass Filter to out-of-band interference.
Drawings
FIG. 1 is a schematic diagram of a circuit structure of a 4-Phase N-path Filter of an on-chip integrated RF band-pass Filter circuit according to the present invention;
fig. 2 is a schematic diagram of the input impedance characteristic (Flo =2GHz) of the Figure N-path Filter of the on-chip integrated rf bandpass Filter circuit according to the present invention;
FIG. 3 is a schematic diagram of an approximate formula of an input impedance of an N-path Filter of an on-chip integrated radio frequency band-pass Filter circuit near a local oscillation frequency according to the present invention;
FIG. 4 shows an on-chip integrated RF band-pass Filter with N-path Filter at ωLOAnd ωTXThe input impedance value formula at the frequency is shown schematically;
FIG. 5 is a schematic diagram of a formula of a suppression ratio of an N-path Filter to TX Leakage interference of an on-chip integrated radio frequency band-pass Filter circuit according to the present invention;
FIG. 6 is a schematic diagram of TXREJ expressions of an on-chip integrated RF bandpass filter circuit according to the present invention;
fig. 7 shows the NPF of the Figure Dual Mixer structure of an on-chip integrated rf bandpass filter circuit and the input impedance characteristics thereof.
Fig. 8 is an expanded view of fig. 7.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to 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.
The invention discloses an on-chip integrated radio frequency band-pass filter circuit, which mainly comprises switches P1, P2, P3 and P4, a capacitor and an inductor;
wherein, the first switch group and the second switch group are respectively composed of switches P1, P2, P3 and P4; the first switch groups P1, P2, P3 and P4 are connected in parallel and are connected with the respective transimpedance amplifiers; the input impedance Zin is connected with the first switch group and the second switch group; the P2 of the second switch group is connected with the P1 of the first switch group in parallel; the P1 of the second switch group is connected with the P2 of the first switch group in parallel; the P4 of the second switch group is connected with the P3 of the first switch group in parallel; the P3 of the second switch group is connected with the P4 of the first switch group in parallel; capacitances are provided between P1 and P2 and P3 and P4.
The circuit structure of the 4-Phase N-path Filter is realized by a 25% duty ratio quadrature passive mixer, wherein ZBB is a load of an analog baseband (BB) and is equivalent to the parallel impedance of a resistor RBB and a capacitor CBB;
the input impedance Zin is connected in parallel with the circuit configuration of the 4-Phase N-path Filter.
Approximate formula of input impedance of path Filter in the vicinity of local oscillation frequency, as shown in FIG. 3Wherein, in the step (A),R SW,NP is the on-resistance of the passive mixer switch, and in order to realize the maximum suppression of TX Leakage interference, the band-pass filter is required to be at omegaTXThe impedance at frequency is as small as possible. N-path Filter at omegaLOAnd ωTXThe value of the input impedance at frequency is approximately as in fig. 4.
The inhibition ratio of the N-path Filter to the TX Leakage interference can be further calculated as follows: as shown in fig. 5, it is found from the formula that, if the baseband impedance CBB is sufficiently large,Z NP (ω TX )minimum on-resistance of switch capable of being approximated to passive mixerR SW,NP To do soR NP (ω LO )Can be designed to be approximately equal toR S Therefore, the above formula can be simplified, and a simpler and more intuitive TXREJ expression is obtained: as shown in fig. 6, it can be seen that Rejection of TX Leakage interference is limited to two parameters,R S andR SW,NP whereinR S In the actual chain, the output impedance of the front stage LNA isR SW,NP I.e. the switch on-resistance of the passive mixer. In order to realize sharper band-pass filtering, it is necessary to reduce the band-pass filtering as much as possibleR SW,NP Or increase in value ofR S I.e. the output impedance of the LNA.
Please refer to fig. 7 and 8: the filter circuit mainly comprises switches P1, P2, P3 and P4, a capacitor and an inductor; wherein, the first switch group and the second switch group are respectively composed of switches P1, P2, P3 and P4; the first switch groups P1, P2, P3 and P4 are connected in parallel and are connected with the respective transimpedance amplifiers; the input impedance Zin is connected with the first switch group and the second switch group; the P2 of the second switch group is connected with the P1 of the first switch group in parallel; the P1 of the second switch group is connected with the P2 of the first switch group in parallel; the P4 of the second switch group is connected with the P3 of the first switch group in parallel; the P3 of the second switch group is connected in parallel with the P4 of the first switch group, and the capacitors are arranged between the P1 and the P2 and between the P3 and the P4. Certain aspects of the present disclosure provide N-channel filters with wider passbands and steeper rejection than conventional N-channel filters having only a single pole in each filter path. These N-channel filters also have flatter passbands with reduced passband dip. One example N-channel filter includes a plurality of branches selectively connected to a common node, each branch of the N-channel filter including a switch connected in series with an impedance having a common-drain amplifier circuit. In certain aspects, the amplifier circuit may include a degeneration circuit for stability and/or a multi-phase feedback circuit for reducing in-band peaks.
To further improve the suppression of out-of-band interference, the Passive Mixer in the N-path Filter may be implemented as a Dual Mixer structure. On the basis of the original switch, a reverse LO-driven switch and a series capacitor are connected in parallel. At TX Leakage frequency, CMIXCan be seen as a short circuit, so the input impedance of the NPF is at ω TX1/2, which is a further reduction of the impedance of a Mixer switch, becomesR SW,NP And 2, the filtering performance of the LNA output end to the TX packer is further improved.
The invention has the beneficial effects that: the radio frequency band-pass Filter circuit integrated on the chip adopts a structure called N-path Filter (NPF) to realize a required band-pass Filter, solves the problem that the existing band-pass Filter is not sharp enough, and improves the inhibition of the existing band-pass Filter to out-of-band interference.
It should be noted that the foregoing is only a preferred embodiment of the invention and the technical principles employed, and those skilled in the art will understand that the invention is not limited to the specific embodiments described herein, and that various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (5)
1. An on-chip integrated radio frequency band-pass filter circuit, characterized by: the filter circuit mainly comprises switches P1, P2, P3 and P4, a capacitor and an inductor;
wherein, the first switch group and the second switch group are respectively composed of switches P1, P2, P3 and P4; the first switch groups P1, P2, P3 and P4 are connected in parallel and are connected with the respective transimpedance amplifiers; the input impedance Zin is connected with the first switch group and the second switch group; the P2 of the second switch group is connected with the P1 of the first switch group in parallel; the P1 of the second switch group is connected with the P2 of the first switch group in parallel; the P4 of the second switch group is connected with the P3 of the first switch group in parallel; the P3 of the second switch group is connected with the P4 of the first switch group in parallel; the capacitor is arranged between P1 and P2 and between P3 and P4, and the circuit structure of the 4-Phase N-path Filter is realized by a 25% duty ratio quadrature passive mixer, wherein ZBB is a load of an analog baseband (BB) and is equivalent to the parallel impedance of a resistor RBB and a capacitor CBB;
the input impedance Zin is connected in parallel with the circuit configuration of the 4-Phase N-path Filter.
2. The on-chip integrated radio frequency band-pass filter circuit according to claim 1, wherein due to the mutual communication characteristic between the RF end and the BB end of the passive mixer, there is almost no isolation, when the RF signal is down-converted to the BB end, the RF signal is shaped and filtered by the impedance of the BB end, and then the shaped BB signal is up-converted by the passive mixer and fed through to the RF end, and the up-converted signal shifts the impedance characteristic of the BB end to the local oscillation frequency, thereby forming the high Q value band-pass filter characteristic of the radio frequency end.
3. An on-chip integrated radio frequency band-pass filter circuit as claimed in claim 1, wherein in some aspects the amplifier circuit may include a degeneration circuit for stability and/or a polyphase feedback circuit for reducing in-band peaks.
4. An on-chip integrated rf bandpass Filter circuit according to claim 1, wherein, to further improve the suppression of out-of-band interference, the Passive Mixer in the N-path Filter can be implemented as a Dual Mixer structure.
5. An on-chip integrated rf bandpass filter circuit according to claim 1, wherein C is at the TX Leakage frequencyMIXCan be seen as a short circuit, so the input impedance of the NPF is at ωTX1/2, which is a further reduction of the impedance of a Mixer switch, becomesR SW,NP And 2, further improving the filtering of the output end of the LNA to the TX Blocker.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110344216.XA CN113242028A (en) | 2021-03-31 | 2021-03-31 | On-chip integrated radio frequency band-pass filter circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110344216.XA CN113242028A (en) | 2021-03-31 | 2021-03-31 | On-chip integrated radio frequency band-pass filter circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113242028A true CN113242028A (en) | 2021-08-10 |
Family
ID=77130858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110344216.XA Pending CN113242028A (en) | 2021-03-31 | 2021-03-31 | On-chip integrated radio frequency band-pass filter circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113242028A (en) |
-
2021
- 2021-03-31 CN CN202110344216.XA patent/CN113242028A/en active Pending
Non-Patent Citations (1)
| Title |
|---|
| HAJIR HEDAYATI等: "A 1.8 dB NF Blocker-Filtering Noise-Canceling Wideband Receiver With Shared TIA in 40 nm CMOS", 《IEEE JOURNAL OF SOLID-STATE CIRCUITS》, vol. 50, no. 5, pages 1148 - 1164, XP011579932, DOI: 10.1109/JSSC.2015.2403324 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10128819B2 (en) | High rejection wideband bandpass N-path filter | |
| KR101516857B1 (en) | System and method for a radio frequency switch | |
| JP4278868B2 (en) | Harmonic rejection in dual-band mobile phones | |
| EP3039790B1 (en) | Blocker filtering for noise-cancelling receiver | |
| GB2577164A (en) | Parallel hybrid acoustic passive filter | |
| Mikhemar et al. | A tunable integrated duplexer with 50dB isolation in 40nm CMOS | |
| US9136815B2 (en) | Methods and apparatuses for implementing variable bandwidth RF tracking filters for reconfigurable multi-standard radios | |
| JP2017501658A (en) | A device comprising a first resonant tank, a second resonant tank and a shunt capacitor | |
| CN114095049B (en) | Radio frequency receiving and transmitting switch circuit, radio frequency front-end circuit and radio frequency transceiver | |
| US9847772B2 (en) | N-path filters with flatter frequency response | |
| US10020793B2 (en) | Integrated filters in output match elements | |
| Krishnamurthy et al. | Enhanced passive mixer-first receiver driving an impedance with 40dB/decade roll-off, achieving+ 12dBm blocker-P1dB,+ 33dBm IIP3 and sub-2dB NF degradation for a 0dBm blocker | |
| CN110999132A (en) | Selectable filtering by switching | |
| US11601115B2 (en) | Electronic RF filter | |
| Abdulaziz et al. | Improving Receiver Close-In Blocker Tolerance by Baseband $ G_m-C $ Notch Filtering | |
| US9559735B2 (en) | Switching resonator filter circuits and methods | |
| KR20200060844A (en) | Front end module | |
| CN113972926B (en) | Radio frequency receiving and transmitting switch circuit, radio frequency front-end circuit and radio frequency transceiver | |
| Nguyen et al. | Low power, high linearity wideband receiver front-end for LTE application | |
| US20130336342A1 (en) | Method and Device For Implementing Tracking Filters and RF Front End of Software Defined Radios | |
| Hasan et al. | Tunable blocker-tolerant RF front-end filter with dual adaptive notches for reconfigurable receivers | |
| CN113242028A (en) | On-chip integrated radio frequency band-pass filter circuit | |
| CN111277223B (en) | High-order coupling network with interference suppression and application thereof | |
| JPH10135708A (en) | Filter for branching device | |
| Jin et al. | An FDD Auxiliary Receiver with a Highly Linear Low Noise Amplifier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |