A defect-based structure based wideband bias-tee, radio frequency circuit and device

Abstract

The application discloses a wide-band bias device based on a defect ground structure, a radio frequency circuit and equipment, which comprises a radio frequency signal input feed line, a direct current radio frequency mixed signal output feed line, a direct current signal input feed line, a direct current isolation unit and a radio frequency choke unit. The application forms a coupling path-transmission pole joint tuning mechanism in the vertical direction by jointly regulating the finger width / spacing parameters of the interdigital capacitor and the slot line topology of the ground plane resonant defect ground structure, expands the radio frequency passband to a super wide band without increasing the circuit area; and based on the matching of the high impedance line characteristic impedance and the etching width / length parameters of the ground plane notch defect ground structure, the ground current distribution of the radio frequency path is disturbed, the in-band coupling resonance is suppressed, the direct current end isolation degree is improved, and the isolation bandwidth is widened synchronously with the radio frequency passband. The application relates to the technical field of radio frequency devices.

Description

Technical Field

[0001] This application relates to the field of radio frequency device technology, and in particular to a wideband biaser, radio frequency circuit and device based on a defective ground structure. Background Technology

[0002] In millimeter-wave communication and RF front-end systems, biasers are core components that enable the coordinated operation of active device DC drive and RF signal transmission. Active devices such as power amplifiers and low-noise amplifiers rely on stable DC bias voltages to maintain gain and linearity. Biasers, through RF chokes, block RF signals from entering the DC source, while simultaneously using DC blocking to prevent DC components from interfering with the RF link, ensuring efficient signal transmission over a wide bandwidth. With the evolution of technologies such as 5G / 6G and millimeter-wave radar, the bandwidth and efficiency requirements for active devices have increased dramatically, and the bandwidth and isolation performance of biasers directly constrain the overall link performance and integration.

[0003] The publicly available distributed biaser structures are as follows: (1) The 2019 IEEE Region 10 Conference (TENCON) international proceedings included a paper entitled "Compact Ka Band Bias Tee Network Using Substrate Integrated Coaxial Line Technology", which proposed a biaser based on interdigital capacitors and a butterfly stub. This design uses a six-finger interdigital capacitor structure and achieves a relative bandwidth of 12% in the 31-35GHz band through substrate integrated coaxial line technology. However, its DC end has insufficient RF signal suppression due to the butterfly stub structure, resulting in an isolation of only 22dB. (2) In 2021, the IEEE Microwave and Wireless Components Letters, Volume 10, published a paper entitled “Design of DC-Blocks and Bias-Tee on PCB for V-Band”, which reported a biaser based on a triangular-interdigital composite structure and a fan-shaped stub high-impedance microstrip line. The triangular structure was added to the interdigital capacitor to improve the interdigital coupling strength and achieve a relative bandwidth of 48% within the 60 GHz center frequency. However, due to the narrow frequency range of the fan-shaped stub, the isolation dropped to 20 dB at the passband edge.

[0004] In summary, the publicly disclosed biasers have insufficient passband bandwidth, and the DC isolation of the biasers is insufficient with an excessively narrow isolation bandwidth. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a wideband biaser based on a defective ground structure, which can improve the passband bandwidth of the biaser.

[0006] This application also proposes a radio frequency circuit and device having the above-mentioned wideband biaser based on the defective ground structure.

[0007] A broadband biaser based on a defective ground structure according to a first aspect embodiment of this application includes an RF signal input feeder, a DC-RF mixed signal output feeder, a DC signal input feeder, a DC blocking unit, and an RF choke unit, wherein:

[0008] The two ends of the DC blocking unit are respectively connected to the RF signal input feed line and the DC RF mixed signal output feed line, and the three together form an RF signal path; the two ends of the RF choke unit are respectively connected to the DC signal input feed line and the DC RF mixed signal output feed line, and the three together form a DC signal path.

[0009] The DC blocking unit includes an interdigital capacitor and a resonant defect ground structure disposed below the interdigital capacitor;

[0010] The radio frequency choke unit includes a high-impedance microstrip line and a notch defect ground structure disposed below the high-impedance microstrip line.

[0011] The wideband biaser based on the defective ground structure according to the embodiments of this application has at least the following beneficial effects: The present invention forms a coupled path-transmission pole joint tuning mechanism in the vertical direction by jointly controlling the finger width / spacing parameters of the interdigital capacitor and the slot topology of the ground plane resonant defective ground structure, thereby extending the RF passband to an ultra-wideband without increasing the circuit area; moreover, based on the matching of the characteristic impedance of the high impedance line with the etching width / length parameters of the ground plane notch defective ground structure, the ground current distribution of the RF path is disturbed, suppressing in-band coupled resonance, thereby improving the DC end isolation and simultaneously widening the isolation bandwidth and RF passband.

[0012] According to some embodiments of this application, the broadband biaser based on the defective ground structure further includes a dielectric substrate and a ground metal layer covering the bottom of the dielectric substrate. The RF signal input feed line, the DC RF mixed signal output feed line, the DC signal input feed line, the interdigital capacitor, and the high impedance microstrip line are all disposed on the top of the dielectric substrate. The resonant defective ground structure and the notch defective ground structure are etched on the ground metal layer.

[0013] According to some embodiments of this application, the materials of the RF signal input feed line, the DC-RF mixed signal output feed line, the DC signal input feed line, the interdigital capacitor, and the high-impedance microstrip line are all metals.

[0014] According to some embodiments of this application, the high-impedance microstrip line overlaps with the notch defect ground structure in the vertical direction, forming interlayer coupling; the interdigital capacitor overlaps with the resonant defect ground structure in the vertical direction, forming interlayer coupling.

[0015] According to some embodiments of this application, the radio frequency signal input feed line, the DC-RF mixed signal output feed line, and the DC signal input feed line are all microstrip transmission lines.

[0016] According to some embodiments of this application, the notch defect grounding structure includes a connecting portion and two rectangular portions, with the two rectangular portions respectively disposed at both ends of the connecting portion.

[0017] According to some embodiments of this application, the resonant defect ground structure is an annular groove defect ground structure or a V-shaped groove defect ground structure.

[0018] According to some embodiments of this application, the interdigital capacitor includes at least two interdigital structures that are interleaved with each other.

[0019] The radio frequency circuit according to the second aspect of this application includes the wideband biaser based on the defective ground structure described above.

[0020] The device according to a third aspect of this application includes the radio frequency circuit described above.

[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0022] The accompanying drawings are used to provide a further understanding of the technical solutions disclosed in this application and form part of the specification. They are used together with the embodiments disclosed in this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions disclosed in this application.

[0023] Figure 1 A three-dimensional diagram of a broadband biaser based on a defective ground structure according to an embodiment of the first aspect of this application;

[0024] Figure 2 This is a schematic diagram showing the positional relationship between the high-impedance microstrip line and the notch filter defective ground structure in a broadband biaser based on a defective ground structure according to the first aspect of this application.

[0025] Figure 3 This is a schematic diagram showing the positional relationship between the interdigital capacitor and the resonant defective ground structure in a broadband biaser based on a defective ground structure according to the first aspect embodiment of this application;

[0026] Figure 4The return loss (S) of a broadband biaser based on a defective ground structure according to the first aspect embodiment of this application is... 11 ) and insertion loss (S 21 Performance diagram;

[0027] Figure 5 The DC-side isolation (S) of a broadband biaser based on a defective ground structure according to the first aspect embodiment of this application. 31 S 32 Performance diagram.

[0028] Reference numerals: 100-RF signal input feeder, 200-DC RF mixed signal output feeder, 300-DC signal input feeder, 400-DC blocking unit, 410-interdigital capacitor, 411-interdigital structure, 420-resonant defect ground structure, 500-RF choke unit, 510-high impedance microstrip line, 520-notch defect ground structure, 600-dielectric substrate, 700-ground metal layer. Detailed Implementation

[0029] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0030] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0031] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0032] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0033] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] In millimeter-wave communication and RF front-end systems, biasers are core components that enable the coordinated operation of active device DC drive and RF signal transmission. Active devices such as power amplifiers and low-noise amplifiers rely on stable DC bias voltages to maintain gain and linearity. Biasers, through RF chokes, block RF signals from entering the DC source, while simultaneously using DC blocking to prevent DC components from interfering with the RF link, ensuring efficient signal transmission over a wide bandwidth. With the evolution of technologies such as 5G / 6G and millimeter-wave radar, the bandwidth and efficiency requirements for active devices have increased dramatically, and the bandwidth and isolation performance of biasers directly constrain the overall link performance and integration.

[0035] The publicly available distributed biaser structures are as follows: (1) The 2019 IEEE Region 10 Conference (TENCON) international proceedings included a paper entitled "Compact Ka Band Bias Tee Network Using Substrate Integrated Coaxial Line Technology", which proposed a biaser based on interdigital capacitors and a butterfly stub. This design uses a six-finger interdigital capacitor structure and achieves a relative bandwidth of 12% in the 31-35GHz band through substrate integrated coaxial line technology. However, its DC end has insufficient RF signal suppression due to the butterfly stub structure, resulting in an isolation of only 22dB. (2) In 2021, the IEEE Microwave and Wireless Components Letters, Volume 10, published a paper entitled “Design of DC-Blocks and Bias-Tee on PCB for V-Band”, which reported a biaser based on a delta-interdigital composite structure and a fan-shaped stub high-impedance microstrip line. The delta-interdigital composite structure adds a delta structure to the interdigital capacitor to improve the inter-coupling strength and achieves a relative bandwidth of 48% within the 60GHz center frequency. However, due to the narrow applicable frequency range of the fan-shaped stub, the isolation drops to 20dB at the passband edge.

[0036] In summary, the publicly disclosed biasers have insufficient passband bandwidth, and the DC isolation of the biasers is insufficient with an excessively narrow isolation bandwidth.

[0037] To address this, this application proposes a wideband biaser based on a defective ground structure. By jointly controlling the finger width / spacing parameters of the interdigital capacitors and the slot topology of the ground plane resonant defective ground structure, a coupled path-transmission pole joint tuning mechanism is formed in the vertical direction. This extends the RF passband to an ultra-wideband without increasing the circuit area. Furthermore, by matching the characteristic impedance of the high-impedance line with the etching width / length parameters of the ground plane notch defective ground structure, the ground current distribution of the RF path is disturbed, suppressing in-band coupled resonance, thereby improving DC-end isolation and simultaneously widening the isolation bandwidth and RF passband.

[0038] In addition, this application also proposes a radio frequency circuit including the above-described wideband bias circuit based on a defective ground structure, and an apparatus including the radio frequency circuit.

[0039] Reference Figure 1 The wideband biaser based on a defective ground structure in the first aspect embodiment of this application includes an RF signal input feed line 100, a DC-RF mixed signal output feed line 200, a DC signal input feed line 300, a DC blocking unit 400, and an RF choke unit 500, wherein:

[0040] The two ends of the DC blocking unit 400 are connected to the RF signal input feed line 100 and the DC-RF mixed signal output feed line 200, respectively, and the three together form an RF signal path. The two ends of the RF choke unit 500 are connected to the DC signal input feed line 300 and the DC-RF mixed signal output feed line 200, respectively, and the three together form a DC signal path.

[0041] For the specific structure of the DC blocking unit 400 and the RF choke unit 500, please refer to... Figure 2 The DC blocking unit 400 includes an interdigital capacitor 410 and a resonant defect ground structure 420 disposed below the interdigital capacitor 410. The two ends of the interdigital structure 410 are respectively connected to the RF signal input feed line 100 and the DC RF mixed signal output feed line 200. The RF choke unit 500 includes a high-impedance microstrip line 510 and a notch defect ground structure 520 disposed below the high-impedance microstrip line 510. The two ends of the high-impedance microstrip line 510 are respectively connected to the DC signal input feed line 300 and the DC RF mixed signal output feed line 200.

[0042] Furthermore, the broadband biaser based on the defect ground structure also includes a dielectric substrate 600 and a ground metal layer 700 covering the bottom of the dielectric substrate 600. The dielectric substrate 600 uses Rogers 5880 substrate material with a dielectric constant of 2.2 and a loss tangent of 0.0009. RF signal input feed line 100, DC RF mixed signal output feed line 200, DC signal input feed line 300, interdigital capacitor 410, and high-impedance microstrip line 510 are all disposed on the top of the dielectric substrate 600, and resonant defect ground structure 420 and notch filter defect ground structure 520 are etched on the ground metal layer 700.

[0043] Furthermore, the materials of the RF signal input feed line 100, the DC-RF mixed signal output feed line 200, the DC signal input feed line 300, the interdigital capacitor 410, and the high-impedance microstrip line 510 are all metals, specifically copper, with a thickness of 1 oz. Using this material is beneficial for the transmission of DC and RF signals.

[0044] Furthermore, the high-impedance microstrip line 510 and the notch defect ground structure 520 overlap vertically, forming interlayer coupling, which achieves the effect of DC-end suppression enhancement by perturbing the ground plane current distribution. The interdigital capacitor 410 and the resonant defect ground structure 420 overlap vertically, forming interlayer coupling, which effectively expands the passband bandwidth by adjusting the transmission pole distribution.

[0045] Furthermore, the RF signal input feed line 100, the DC-RF mixed signal output feed line 200, and the DC signal input feed line 300 are all microstrip transmission lines. The RF signal input feed line 100 and the DC-RF mixed signal output feed line 200 are microstrip transmission lines with a characteristic impedance of 50 ohms or 75 ohms, which can quickly achieve impedance matching when interconnecting with other RF devices.

[0046] Furthermore, the RF signal input feed line 100, the DC RF mixed signal output feed line 200, and the DC signal input feed line 300 are all flush with the side edge of the dielectric substrate 600 to facilitate connection with other RF devices.

[0047] Furthermore, as one embodiment, the notch defect structure 520 includes a connecting portion and two rectangular portions, which are respectively disposed at both ends of the connecting portion to form a dumbbell or H-shaped structure, so that it can generate at least one notch characteristic with an attenuation depth greater than -20dB within the target frequency.

[0048] Furthermore, as one embodiment, the resonant defect ground structure 420 can be an annular groove defect ground structure or a V-shaped groove defect ground structure, so that it can generate at least one resonant point within the target frequency.

[0049] Furthermore, as one embodiment, the interdigital capacitor 410 may include at least two interdigital structures 411 arranged in an interleaved manner. The width of the interdigital structure 411 is 0.15 mm, and the spacing between the interdigital structures 411 is 0.1 mm. The number of interdigital structures 411 can be increased or decreased according to actual needs, which will not be elaborated here.

[0050] This embodiment provides a wideband biaser design based on a defective ground structure. Building upon a traditional planar structure, by coordinating the resonant defective ground structure 420 and the notch filter defective ground structure 520, and combining the joint tuning of the finger width / spacing parameters of the interdigital capacitor 410 with the impedance value of the high-impedance microstrip line 510, the operating bandwidth of the biaser is significantly broadened, while simultaneously improving DC-side isolation and isolation bandwidth. This design fully utilizes the inherent space of the ground plane, requiring no additional circuit area expansion, and is implemented using a single-layer etching process, offering advantages in both ease of fabrication and low cost.

[0051] A radio frequency circuit according to a second aspect of this application includes the aforementioned wideband biaser based on a defective ground structure.

[0052] An apparatus according to a third aspect of this application includes the radio frequency circuit described above.

[0053] Performance tests were conducted on this broadband biaser based on a defective ground structure, referring to... Figure 4 The biaser has a center frequency of 15 GHz, a return loss of -23.6 dB, a 3 dB bandwidth of 112.5%, and an in-band insertion loss of less than 0.44 dB in the 10-20 GHz range. The introduction of the resonant defect ground structure 420 in this invention significantly improves the biaser bandwidth. Compared with currently disclosed RF biasers, the RF passband performance of this embodiment has a significant wideband advantage, with the bandwidth more than doubled. Figure 5 The DC-side isolation performance of this bias unit was demonstrated, achieving an isolation level greater than 33.2 dB in the 10 to 20 GHz range, with a maximum isolation level of 46.3 dB. Due to the introduction of the notch-defect ground structure 520, this bias unit exhibits a deeper suppression depth and a wider suppression bandwidth, significantly improving isolation performance compared to traditional solutions.

[0054] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A broadband biaser based on a defective ground structure, characterized in that, It includes an RF signal input feeder, a DC / RF mixed signal output feeder, a DC signal input feeder, a DC blocking unit, and an RF choke unit, wherein: The two ends of the DC blocking unit are respectively connected to the RF signal input feed line and the DC RF mixed signal output feed line, and the three together form an RF signal path; the two ends of the RF choke unit are respectively connected to the DC signal input feed line and the DC RF mixed signal output feed line, and the three together form a DC signal path. The DC blocking unit includes an interdigital capacitor and a resonant defect ground structure disposed below the interdigital capacitor; The radio frequency choke unit includes a high-impedance microstrip line and a notch defect ground structure disposed below the high-impedance microstrip line. The broadband biaser based on the defective ground structure forms a joint tuning mechanism of coupling path-transmission pole in the vertical direction by jointly controlling the finger width / spacing parameters of the interdigital capacitor and the slot topology of the resonant defective ground structure. The characteristic impedance of the high-impedance line is matched with the etching width / length parameters of the notch defect ground structure.

2. The broadband biaser based on defective ground structure according to claim 1, characterized in that: The broadband biaser based on the defective ground structure further includes a dielectric substrate and a ground metal layer covering the bottom of the dielectric substrate. The RF signal input feed line, the DC RF mixed signal output feed line, the DC signal input feed line, the interdigital capacitor, and the high impedance microstrip line are all disposed on the top of the dielectric substrate. The resonant defective ground structure and the notch defective ground structure are etched on the ground metal layer.

3. The broadband biaser based on defective ground structure according to claim 2, characterized in that: The materials of the RF signal input feed line, the DC-RF mixed signal output feed line, the DC signal input feed line, the interdigital capacitor, and the high-impedance microstrip line are all metal.

4. The broadband biaser based on defective ground structure according to claim 1, characterized in that: The high-impedance microstrip line overlaps with the notch defect ground structure in the vertical direction, forming interlayer coupling; the interdigital capacitor overlaps with the resonant defect ground structure in the vertical direction, forming interlayer coupling.

5. The broadband biaser based on defective ground structure according to claim 1, characterized in that: The radio frequency signal input feed line, the DC-RF mixed signal output feed line, and the DC signal input feed line are all microstrip transmission lines.

6. The broadband biaser based on defective ground structure according to claim 1, characterized in that: The notch defect structure includes a connecting portion and two rectangular portions, with the two rectangular portions respectively disposed at both ends of the connecting portion.

7. The broadband biaser based on defective ground structure according to claim 1, characterized in that: The resonant defect ground structure is either an annular groove defect ground structure or a V-shaped groove defect ground structure.

8. The broadband biaser based on defective ground structure according to claim 1, characterized in that: The interdigitated capacitor includes at least two interdigitated structures arranged in an alternating manner.

9. A radio frequency circuit, characterized in that, Includes the broadband biaser based on defective ground structure as described in any one of claims 1 to 8.

10. A device, characterized in that, Includes the radio frequency circuit described in claim 9.

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