Millimeter-wave low-pass / high-pass reconfigurable filter

Abstract

The present invention relates to a millimeter-wave low-pass / high-pass reconfigurable filter, comprising a series-parallel reconfiguration structure, a passband compensation inductor, and a ground-direct connection reconfiguration structure, capable of achieving the interchange of a passband and a stopband of the filter in two modes, reconfigurable output in both high and low bands, low loss at the passband and good mirror signal suppression at the stopband, and hardware reuse. The millimeter-wave low-pass / high-pass reconfigurable filter of the present invention has a simple circuit structure, and is suitable for use in a multi-band millimeter-wave reconfigurable transceiver.

Description

A millimeter-wave low-pass and high-pass reconfigurable filter Technical Field

[0001] The present invention relates to a millimeter wave low-pass and high-pass reconfigurable filter circuit for filtering signals of different frequency bands through reconfigurable technology, which is used in microwave and millimeter wave integrated circuits and belongs to the technical field of filters. Background Art

[0002] The millimeter wave band, with its advantages of high frequency, wide bandwidth, and abundant spectrum resources, has become a research focus for realizing compact, high-speed, and highly sensitive wireless communication systems. It holds promising application prospects in a wide range of fields, including communications and radar. Furthermore, as lower-frequency spectrum resources have been widely used and are gradually becoming depleted, the millimeter wave band has become the preferred choice for high-speed wireless data transmission. Currently, the spectrum for fifth-generation mobile communication technology is divided into two bands: the FR1 Sub6G band (450MHz-7GHz), a low-frequency band primarily at 3.5GHz that features long transmission distances and strong signal penetration, making it the primary frequency band for 5G. The other band is the FR2 millimeter wave band (24-100GHz), which boasts 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 communications can further expand communication bandwidth by utilizing multiple frequency bands. Technical issues

[0003] Millimeter-wave filters, including low-pass filters, high-pass filters, and bandpass filters, are key modules in the millimeter-wave transceiver front-end. Currently, millimeter-wave filters for various frequency bands have been developed, but most designs operate within a fixed frequency band. Very few millimeter-wave filters can simultaneously select signals from different frequency bands, and no millimeter-wave filters have yet been found that can filter across multiple frequency bands while also exhibiting stop-band suppression. When future millimeter-wave communication systems operate in multiple frequency bands to achieve greater communication capacity and more flexible communication networking, the continued use of switching millimeter-wave filter circuits operating in multiple fixed frequency bands will significantly complicate the communication system, resulting in high cost, power consumption, and size, making it difficult to adapt to the demands of multi-frequency wireless communication systems, especially mobile devices. Therefore, developing millimeter-wave filter structures that can operate in different frequency bands will enable hardware circuit reuse, simplify the communication system architecture, and reduce cost and power consumption. Technical Solutions

[0004] In order to overcome the shortcomings of existing research, the present invention provides a millimeter-wave low-pass and high-pass reconfigurable filter that can interchange the filter passband and stopband in two modes, realize reconfigurable filtering output in multiple frequency bands, and exhibit low passband loss and good image signal suppression in the stopband.

[0005] A millimeter-wave low-pass and high-pass reconfigurable filter, comprising a series-parallel reconstruction structure, a passband compensation inductor, and a ground-direct connection reconstruction structure;

[0006] The series-parallel reconfiguration structure is composed of a parallel resonant network of a first switch, a second switch, a third switch, a first inductor, and a first capacitor; the input end is connected to one end of the first switch and the second switch, the other end of the first switch is connected to the first capacitor and one end of 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 above structures together 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 out the passband capacitance of the series-parallel reconstruction structure;

[0008] The ground-to-direct connection reconstruction structure is composed of a series resonant network of a fourth switch, a fifth switch, a sixth switch, a third inductor, and a second capacitor; the other end of the fourth switch is connected to 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 end, 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 connection reconstruction structure.

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

[0010] Preferably, the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch all adopt NMOS-type switch tubes, whose gates are the switch control terminals, and the source and drain are the two ends of the switches respectively; when the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch are turned on, the NMOS-type switch tubes are equivalent to resistors, and when turned off, the NMOS-type switch tubes are equivalent to capacitors, and the resonant frequencies of the series and parallel networks are changed by simultaneously switching the switch control signals to achieve the reconfigurable frequency output of the filter.

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

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

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

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

[0015] A millimeter-wave low-pass and high-pass reconfigurable filter first realizes the interchangeability of the filter passband and stopband in two modes, and secondly achieves lower passband loss and good image signal suppression in the stopband; by using a low-pass / high-pass reconfigurable structure, multiple frequency bands are output in low and high frequency bands. Beneficial effects

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[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 the present invention not only enables interchangeability of the filter passband and stopband in two modes, but also simultaneously achieves low loss in the passband and good signal suppression in the stopband. This is a reconfigurable filter circuit with image signal suppression. Conventional filter structures can only filter out millimeter-wave signals within a fixed frequency band, limiting their application in multi-frequency communication systems.

[0019] 3. The millimeter-wave low-pass and high-pass reconfigurable filter circuit structure of the present invention is simple, reconfigurable and controllable, and has few components and is easy to implement, which can effectively reduce cost and power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] FIG1 is a structural diagram of a millimeter-wave low-pass and high-pass reconfigurable filter according to the present invention;

[0022] FIG2 is a structural diagram of an equivalent circuit of a first reconfigurable state in the present invention;

[0023] FIG3 is a structural diagram of an equivalent circuit of a second reconfigurable state in the present invention;

[0024] FIG4 is a simulation transmission curve diagram of the millimeter-wave low-pass and high-pass reconfigurable filter of the present invention. Best Mode for Carrying Out the Invention

[0025] The present invention is described by taking a millimeter wave frequency band low-pass and high-pass reconfigurable filter as an example.

[0026] The millimeter-wave frequency band low-pass and high-pass reconfigurable filter in this embodiment is designed using a 65nm CMOS process. The six switches are all composed of NMOS transistors. The gate lengths of switches SW1, SW3, and SW5 are 60nm and the gate widths are 192μm. The gate lengths of switches SW2, SW4, and SW6 are 60nm and the gate widths are 64μm. Their on-control voltage is 1V, and their off-control voltage is 0V. The capacitances of capacitors C1 and C2 are 115fF and 77fF, respectively. The inductors L1, L2, and L3 have inductances of 275pH, 150pH, and 275pH, respectively.

[0027] Circuit simulation tools were used to design and simulate the millimeter-wave low-pass and high-pass reconfigurable filters. When all four switches (SW1, SW3, SW5, and SW6) are on and the two switches (SW2 and SW4) are off, the first reconfigurable low-pass filter circuit is formed, capable of achieving less than 3.4dB of transmission loss in the 24-30GHz band and greater than 17.5dB of stopband signal suppression in the 37-45.5GHz band. When all four switches (SW1, SW3, SW5, and SW6) are off and the two switches (SW2 and SW4) are on, the second reconfigurable high-pass filter circuit is formed, capable of achieving less than 5.2dB of transmission loss in the 37-50GHz band and greater than 16dB of stopband signal suppression in the 24-31.5GHz band. Modes for Carrying Out the Invention

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] As shown in Figure 1, a millimeter-wave low-pass and high-pass reconfigurable filter includes a series-parallel reconstruction structure, a passband compensation inductor, and a ground-direct connection reconstruction structure;

[0030] The series-parallel reconfiguration structure is composed 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 the first capacitor C1 and one end of 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, and the other end of the third switch SW3 is connected to the other end of the first inductor L1; the above structures together constitute the series-parallel reconfiguration structure;

[0031] 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 out the passband capacitance of the series-parallel reconstruction structure;

[0032] The ground-to-direct connection reconstruction structure is composed 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 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 end Out, and the other end of the third inductor L3 is connected to the other end of the second capacitor C2; the above structures together constitute the ground / direct connection reconstruction structure.

[0033] The first switch SW1 , the third switch SW3 , the fifth switch SW5 and the sixth switch SW6 are switched by the same control signal, that is, they are turned on and off at the same time; the second switch SW2 and the fourth switch SW4 are switched by the same control signal, that is, they are turned on and off at the same time.

[0034] In the millimeter-wave low-pass-high-pass reconfigurable filter, the first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, the fifth switch SW5 and the sixth switch SW6 all adopt NMOS type switch tubes, whose gates are switch control terminals, and the source and drain are the two ends of the switches respectively; when the first switch SW1, the third switch SW3, the fifth switch SW5 and the sixth switch SW6 are turned on, the NMOS type switch tubes 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 switch tubes are equivalent to capacitors C OFF2 and C OFF4 The millimeter wave low-pass / high-pass reconfigurable filter structure works in the low-pass mode, as shown in Figure 2. When the first switch SW1, the third switch SW3, the fifth switch SW5 and the sixth switch SW6 are turned off, the NMOS type switch tubes are 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 switch tubes are equivalent to resistors R ON2 and R ON4 , the millimeter-wave low-pass and high-pass reconfigurable filter works in the high-pass mode, as shown in Figure 3. By simultaneously switching the switch control signal, the passband and stopband of the filter in the two modes are interchanged, thereby realizing the reconfigurable frequency output of the filter.

[0035] The capacitors C1, C2 and C3 are MOM capacitors, which have an interdigital structure and a high quality factor and low loss.

[0036] The millimeter-wave low-pass and high-pass reconfigurable filter can interchange the filter passband and stopband in two modes by turning the switch on and off, achieving reconfigurable output in high and low frequency bands, as well as lower loss in the passband and good image signal suppression in the stopband, thereby realizing hardware multiplexing.

Claims

1. A millimeter-wave low-pass and high-pass reconfigurable filter, characterized in that: Including series-parallel reconstruction structure, passband compensation inductor, and ground-direct connection reconstruction structure; The series-parallel reconstruction structure is composed of a parallel resonant network of a first switch, a second switch, a third switch, a first inductor and a first capacitor; the input end is connected to one end of the first switch and the second switch, the other end of the first switch is connected to the first capacitor and one end of 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 the passband capacitor of the series-parallel reconstruction structure; The ground-direct connection reconstruction structure is composed of a fourth switch, a fifth switch, a sixth switch, a third inductor and a second capacitor series resonant network; the other end of the fourth switch is connected to 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 end, and the other end of the third inductor is connected to the other end of the second capacitor.

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

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

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 tube, the third switch tube and the fifth switch tube is 60nm, and the gate width is 192μm; the gate length of the second switch tube, the fourth switch tube and the sixth switch tube is 60nm, and the gate width is 64μm; Its on-control voltage is 1V, and its off-control voltage is 0V.

5. The 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 have an interdigital structure.

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

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

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