A millimeter wave low-pass high-pass reconfigurable filter

Abstract

The application relates to a millimeter wave low-pass high-pass reconfigurable filter, which comprises a series-parallel reconfigurable structure, a passband compensation inductor and a direct connection reconfigurable structure to ground, can realize the interchanging of the passband and the stopband of the filter in two modes, realizes the reconfigurable output of a high-frequency band and a low-frequency band, has low loss at the passband and good mirror signal suppression at the stopband, and realizes hardware multiplexing. The millimeter wave low-pass / high-pass reconfigurable filter circuit structure of the application is simple, and is suitable for use in a multi-frequency band millimeter wave reconfigurable transceiver.

Description

Technical Field

[0001] This invention relates to a millimeter-wave low-pass and high-pass reconfigurable filter circuit that uses reconfigurable technology to filter signals in different frequency bands. It is used in microwave and millimeter-wave integrated circuits and belongs to the field of filter technology. Background Technology

[0002] Millimeter-wave bands, with their advantages of high frequency, high bandwidth, and abundant spectrum resources, have become a research focus for realizing small-size, high-speed, and highly sensitive wireless communication systems, showing promising application prospects in many fields such as communications and radar. Meanwhile, as low-frequency spectrum resources have been widely used and are gradually becoming depleted, millimeter-wave bands have become the preferred choice for high-speed wireless data transmission. Currently, the spectrum for fifth-generation mobile communication technology is divided into two bands: one is the FR1 Sub6GHz band (450MHz-7GHz), a low-frequency band mainly based on 3.5GHz, characterized by long transmission distance and strong signal penetration, which has become the main band for 5G; the other is the FR2 millimeter-wave band (24-100GHz), which has high transmission rates and abundant spectrum resources. The 2019 World Wireless Communications Conference identified 24.25-29.5GHz and 37-43.5GHz as the two mainstream millimeter-wave bands for 5G. Furthermore, to achieve higher communication capacity, millimeter-wave communication can further utilize multiple bands to expand the communication bandwidth.

[0003] Millimeter-wave rate filters, including low-pass, high-pass, and band-pass filters, are key modules in millimeter-wave transceiver front-ends. While millimeter-wave filters operating in various frequency bands are now possible, most designs operate within a fixed frequency band. Millimeter-wave filters capable of simultaneously selecting signals from different frequency bands are very rare, and no millimeter-wave filter has yet been found that can filter multiple frequency bands while simultaneously exhibiting stopband rejection. When future millimeter-wave communication systems operate in multiple frequency bands to achieve greater communication capacity and more flexible networking, using millimeter-wave filter circuits that switch between multiple fixed frequency bands would make the communication system extremely complex, leading to high costs, power consumption, and size, making it unsuitable for multi-frequency wireless communication systems, especially mobile devices. Therefore, developing millimeter-wave filter structures capable of operating in different frequency bands will enable hardware circuit reuse, simplify the communication system architecture, and reduce costs and power consumption. Summary of the Invention

[0004] To overcome the shortcomings of existing research, this invention provides a millimeter-wave low-pass and high-pass reconfigurable filter that enables interchangeability of the filter's passband and stopband in two modes, achieves reconfigurable filter output across multiple frequency bands, and exhibits low passband loss and good image signal suppression at the stopband.

[0005] A millimeter-wave low-pass and high-pass reconfigurable filter includes a series-parallel reconfiguration structure, a passband compensation inductor, and a ground-direct reconfiguration structure.

[0006] The series-parallel reconfiguration structure consists of a first switch, a second switch, a third switch, a first inductor, and a first capacitor connected in parallel resonant network. The input terminal is connected to one end of the first and second switches, the other end of the first switch is connected to one end of the first capacitor and the first inductor, the other end of the second switch is connected to the other end of the first capacitor and one end of the third switch, and the other end of the third switch is connected to the other end of the first inductor. Together, these structures constitute the series-parallel reconfiguration structure.

[0007] The passband compensation inductor is composed of a second inductor; one end of the second inductor is connected to the other end of the third switch and the other end of the first inductor, and the other end of the second inductor is connected to one end of the fourth switch and the fifth switch; the passband compensation inductor can resonate and eliminate the passband capacitance of the series-parallel reconstructed structure.

[0008] The ground-direct-connect reconfiguration structure consists of a fourth switch, a fifth switch, a sixth switch, a third inductor, and a second capacitor in a series resonant network; the other end of the fourth switch is connected to one end of the second capacitor and one end of the sixth switch, and the other end of the sixth switch is grounded; the other end of the fifth switch is connected to one end of the third inductor and the output terminal, and the other end of the third inductor is connected to the other end of the second capacitor; the above structures together constitute the ground / direct-connect reconfiguration structure.

[0009] Preferably, the first, third, fifth, and sixth switches are switched using the same control signal, that is, they are simultaneously turned on and off; the second and fourth switches are switched using the same control signal, that is, they are simultaneously turned on and off.

[0010] Preferably, the first, second, third, fourth, fifth, and sixth switches are all NMOS type switching transistors, with their gates serving as the switch control terminals and their source and drain terminals serving as the two ends of the switch, respectively. When the first, second, third, fourth, fifth, and sixth switches are turned on, the NMOS type switching transistors are equivalent to resistors, and when turned off, they are equivalent to capacitors. The reconfigurable frequency output of the filter is achieved by simultaneously switching the switch control signals to change the resonant frequencies of the series and parallel networks.

[0011] Preferably, the first, second, third, fourth, fifth, and sixth switches are composed of NMOS transistors. The gate length of the first, third, and fifth switches is 60 nm, and the gate width is 192 μm; the gate length of the second, fourth, and sixth switches is 60 nm, and the gate width is 64 μm; their turn-on control voltage is 1 V, and their turn-off control voltage is 0 V.

[0012] Preferably, the first capacitor and the second capacitor are metal-oxide-metal capacitors, and the metal-oxide-metal capacitors adopt an interdigitated structure.

[0013] Preferably, the capacitance of the first capacitor is 115fF and the capacitance of the second capacitor is 77fF.

[0014] Preferably, the inductance values ​​of the first and third inductors are 275 pH, and the inductance value of the second inductor is 150 pH.

[0015] A millimeter-wave low-pass and high-pass reconfigurable filter firstly achieves the interchangeability of the filter's passband and stopband in two modes, and secondly achieves low passband loss and good image signal suppression in the stopband; by using a low-pass / high-pass reconfigurable structure, it realizes output in multiple frequency bands at both low and high frequencies.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. The millimeter-wave low-pass and high-pass reconfigurable filter of the present invention can realize reconfigurable filtering of millimeter-wave signals of different frequency bands, and its circuit structure multiplexing implementation method is very suitable for use in multi-band millimeter-wave transceiver systems.

[0018] 2. The millimeter-wave low-pass and high-pass reconfigurable filter of this invention not only enables interchangeability of the filter's passband and stopband in two modes, but also simultaneously achieves low loss in the passband and good signal suppression in the stopband, making it a reconfigurable filter circuit with image signal suppression capabilities. Conventional filter structures can only filter out millimeter-wave signals in fixed frequency bands, limiting their application in multi-frequency communication systems.

[0019] 3. The millimeter-wave low-pass and high-pass reconfigurable filter circuit of the present invention has a simple structure, convenient reconfigurable control, fewer components, and is easy to implement, which can effectively reduce cost and power consumption. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a structural diagram of the millimeter-wave low-pass and high-pass reconfigurable filter of the present invention;

[0022] Figure 2 This is a diagram of the equivalent circuit structure of the first reconfigurable state in this invention;

[0023] Figure 3 This is the equivalent circuit structure diagram of the second reconfigurable state in this invention;

[0024] Figure 4 This is a simulation transmission curve of the millimeter-wave low-pass and high-pass reconfigurable filter of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, a millimeter-wave low-pass and high-pass reconfigurable filter includes a series-parallel reconfiguration structure, a passband compensation inductor, and a ground-direct reconfiguration structure.

[0027] The series-parallel reconfiguration structure consists of a parallel resonant network of a first switch SW1, a second switch SW2, a third switch SW3, a first inductor L1, and a first capacitor C1. The input terminal In is connected to one end of the first switch SW1 and the second switch SW2. The other end of the first switch SW1 is connected to one end of the first capacitor C1 and the first inductor L1. The other end of the second switch SW2 is connected to the other end of the first capacitor C1 and one end of the third switch SW3. The other end of the third switch SW3 is connected to the other end of the first inductor L1. Together, these structures constitute the series-parallel reconfiguration structure.

[0028] The passband compensation inductor is composed of a second inductor L2; one end of the second inductor L2 is connected to the other end of the third switch SW3 and the other end of the first inductor L1, and the other end of the second inductor L2 is connected to one end of the fourth switch SW4 and the fifth switch SW5; the passband compensation inductor can resonate and eliminate the passband capacitance of the series-parallel reconstructed structure.

[0029] The ground-direct-connect reconfiguration structure consists of a series resonant network of a fourth switch SW4, a fifth switch SW5, a sixth switch SW6, a third inductor L3, and a second capacitor C2. The other end of the fourth switch SW4 is connected to one end of the second capacitor C2 and one end of the sixth switch SW6, and the other end of the sixth switch SW6 is grounded. The other end of the fifth switch SW5 is connected to one end of the third inductor L3 and the output terminal Out, and the other end of the third inductor L3 is connected to the other end of the second capacitor C2. Together, these structures constitute the ground / direct-connect reconfiguration structure.

[0030] The first switch SW1, the third switch SW3, the fifth switch SW5 and the sixth switch SW6 are switched using the same control signal, that is, they are turned on and off simultaneously; the second switch SW2 and the fourth switch SW4 are switched using the same control signal, that is, they are turned on and off simultaneously.

[0031] The millimeter-wave low-pass-high-pass reconfigurable filter uses NMOS transistors for its first switch SW1, second switch SW2, third switch SW3, fourth switch SW4, fifth switch SW5, and sixth switch SW6. The gate of each switch is the control terminal, and the source and drain are the two ends of the switch, respectively. When the first switch SW1, third switch SW3, fifth switch SW5, and sixth switch SW6 are turned on, the NMOS transistors are equivalent to resistors R. ON1 R ON3 R ON5 R ON6 When the second switch SW2 and the fourth switch SW4 are turned off, the NMOS type switching transistors are equivalent to capacitors C. OFF2 and C OFF4 Millimeter-wave low-pass / high-pass reconfigurable filter structures operate in low-pass mode, such as... Figure 2 As shown. When the first switch SW1, the third switch SW3, the fifth switch SW5, and the sixth switch SW6 are turned off, the NMOS type switching transistors are respectively equivalent to capacitors C. OFF1 C OFF3 C OFF5 C OFF6 When the second switch SW2 and the fourth switch SW4 are turned on, the NMOS type switching transistors are equivalent to resistors R respectively. ON2 and R ON4 Millimeter-wave low-pass and high-pass reconfigurable filters operate in high-pass mode, such as... Figure 3 As shown, the passband and stopband of the filter are interchanged in both modes by simultaneously switching the switch control signal, thereby achieving reconfigurable frequency output of the filter.

[0032] The capacitors C1, C2, and C3 are MOM capacitors, which have an interdigitated structure, resulting in a high quality factor and low loss.

[0033] The millimeter-wave low-pass and high-pass reconfigurable filter can switch between the passband and stopband in two modes by turning the switch on and off, achieving reconfigurable output in high-frequency and low-frequency bands, as well as low loss in the passband and good image signal suppression in the stopband, thus realizing hardware multiplexing.

[0034] The present invention will be described using a low-pass and high-pass reconfigurable filter in the millimeter-wave band as an example.

[0035] The millimeter-wave band low-pass and high-pass reconfigurable filter in this embodiment is designed using a 65nm CMOS process. All six switches are composed of NMOS transistors. Switches SW1, SW3, and SW5 have a gate length of 60nm and a gate width of 192μm; switches SW2, SW4, and SW6 have a gate length of 60nm and a gate width of 64μm. Their on-state control voltage is 1V, and their off-state control voltage is 0V. Capacitors C1 and C2 have capacitance values ​​of 115fF and 77fF, respectively; inductors L1, L2, and L3 have inductance values ​​of 275pH, 150pH, and 275pH, respectively.

[0036] The millimeter-wave low-pass and high-pass reconfigurable filter was designed and simulated using circuit simulation tools. With all four switches SW1, SW3, SW5, and SW6 on and both switches SW2 and SW4 off, a first type of reconfigurable low-pass filter circuit was constructed, achieving a transmission loss of less than 3.4 dB in the 24–30 GHz band and a stopband signal suppression of greater than 17.5 dB in the 37–45.5 GHz band. With all four switches SW1, SW3, SW5, and SW6 off and both switches SW2 and SW4 on, a second type of reconfigurable high-pass filter circuit was constructed, achieving a transmission loss of less than 5.2 dB in the 37–50 GHz band and a stopband signal suppression of greater than 16 dB in the 24–31.5 GHz band.

[0037] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A millimeter-wave low-pass and high-pass reconfigurable filter, characterized in that: This includes series-parallel reconfiguration structures, passband compensated inductors, and ground-direct connection reconfiguration structures; The series-parallel reconfiguration structure consists of a first switch, a second switch, a third switch, a first inductor, and a first capacitor connected in parallel resonant network; the input terminal is connected to one end of the first switch and the second switch, the other end of the first switch is connected to one end of the first capacitor and the first inductor, the other end of the second switch is connected to the other end of the first capacitor and one end of the third switch, and the other end of the third switch is connected to the other end of the first inductor. The passband compensation inductor is composed of a second inductor; one end of the second inductor is connected to the other end of the third switch and the other end of the first inductor, and the other end of the second inductor is connected to one end of the fourth switch and the fifth switch; the passband compensation inductor can resonate and eliminate the passband capacitance of the series-parallel reconstructed structure. The ground-direct-connected reconfiguration structure consists of a fourth switch, a fifth switch, a sixth switch, a third inductor, and a second capacitor in a series resonant network; the other end of the fourth switch is connected to one end of the second capacitor and one end of the sixth switch, and the other end of the sixth switch is grounded; the other end of the fifth switch is connected to one end of the third inductor and the output terminal, and the other end of the third inductor is connected to the other end of the second capacitor.

2. The millimeter-wave low-pass and high-pass reconfigurable filter according to claim 1, characterized in that: The first, third, fifth, and sixth switches are switched using the same control signal to achieve simultaneous on and off states; the second and fourth switches are switched using the same control signal to achieve simultaneous on and off states.

3. A millimeter-wave low-pass and high-pass reconfigurable filter according to claim 2, characterized in that: The first, second, third, fourth, fifth, and sixth switches all use NMOS type switching transistors, with their gates serving as the switch control terminals and their source and drain terminals serving as the two ends of the switch, respectively. When the first, second, third, fourth, fifth, and sixth switches are turned on, the NMOS type switching transistors are equivalent to resistors, and when they are turned off, they are equivalent to capacitors. The reconfigurable frequency output of the filter is achieved by simultaneously switching the switch control signals to change the resonant frequencies of the series and parallel networks.

4. A millimeter-wave low-pass and high-pass reconfigurable filter according to claim 3, characterized in that: The first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are composed of NMOS transistors. The gate length of the first switch, the third switch, and the fifth switch is 60nm and the gate width is 192μm; the gate length of the second switch, the fourth switch, and the sixth switch is 60nm and the gate width is 64μm. Its turn-on control voltage is 1V, and its turn-off control voltage is 0V.

5. A millimeter-wave low-pass and high-pass reconfigurable filter according to claim 1, characterized in that: The first capacitor and the second capacitor are metal-oxide-metal capacitors, and the metal-oxide-metal capacitors adopt an interdigitated structure.

6. A millimeter-wave low-pass and high-pass reconfigurable filter according to claim 5, characterized in that: The capacitance of the first capacitor is 115fF, and the capacitance of the second capacitor is 77fF.

7. A millimeter-wave low-pass and high-pass reconfigurable filter according to claim 1, characterized in that: The inductance values ​​of the first and third inductors are 275 pH, and the inductance value of the second inductor is 150 pH.

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