US-20260128757-A1 - MILLIMETER-WAVE LOW-PASS OR HIGH-PASS RECONFIGURABLE FILTER

US20260128757A1US 20260128757 A1US20260128757 A1US 20260128757A1US-20260128757-A1

Abstract

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 is disclosed. It enables the interchange of filter passband and stopband in two modes, achieving reconfigurable output in both high-frequency and low-frequency bands, along with low loss in the passband and effective image signal rejection in the stopband, thereby realizing hardware reuse. The circuit structure of the millimeter-wave low-pass/high-pass reconfigurable filter according to the invention is compact and well-suited for use in multi-band millimeter-wave reconfigurable transceivers.

Inventors

Jincai WEN
Xu Wang

Assignees

HANGZHOU DIANZI UNIVERSITY

Dates

Publication Date: 20260507
Application Date: 20251229
Priority Date: 20230630

Claims (7)

1 . 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; wherein the series-parallel reconfiguration structure is a parallel resonant network comprising a first switch, a second switch, a third switch, a first inductor and a first capacitor; an input terminal is connected to one end of the first switch and one end of the second switch; the other end of the first switch is connected to one end of 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; the other end of the third switch is connected to the other end of the first inductor; the passband compensation inductor includes 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; the other end of the second inductor is connected to one end of a fourth switch and one end of a fifth switch; the passband compensation inductor is configured to resonate out the passband capacitance of the series-parallel reconfiguration structure; and the ground-direct connection reconfiguration structure is a series resonant network comprising 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 one end of the second capacitor and one end of the sixth switch; 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 an output terminal; the other end of the third inductor is connected to the other end of the second capacitor.
2 . The millimeter-wave low-pass/high-pass reconfigurable filter of claim 1 , wherein the first switch, the third switch, the fifth switch, and the sixth switch are configured to be switched using the same control signal to achieve simultaneous turning-on and turning-off; and the second switch and the fourth switch are configured to be switched using the same control signal to achieve simultaneous turning-on and turning-off.
3 . The millimeter-wave low-pass/high-pass reconfigurable filter of claim 2 , wherein the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are all NMOS transistor switches, wherein a gate thereof is a switch control terminal, and a source and a drain thereof are two terminals of the switch respectively; when the first, second, third, fourth, fifth, and sixth switches are turned on, the NMOS transistor switches are equivalent to resistors, and when turned off, the NMOS transistor switches are equivalent to capacitors; 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 . The millimeter-wave low-pass/high-pass reconfigurable filter of claim 3 , wherein the first, second, third, fourth, fifth, and sixth switches are composed of NMOS transistors; the first, third, and fifth transistor switches have a gate length of 60 nm and a gate width of 192 μm; the second, fourth, and sixth transistor switches have a gate length of 60 nm and a gate width of 64 μm; an on-control voltage thereof is 1V, and an off-control voltage thereof is 0V.
5 . The millimeter-wave low-pass/high-pass reconfigurable filter of claim 1 , wherein the first capacitor and the second capacitor are metal-oxide-metal capacitors, and the metal-oxide-metal capacitors employ an interdigitated structure.
6 . The millimeter-wave low-pass/high-pass reconfigurable filter of claim 5 , wherein the capacitance value of the first capacitor is 115 fF, and the capacitance value of the second capacitor is 77 fF.
7 . The millimeter-wave low-pass/high-pass reconfigurable filter of claim 1 , wherein the inductance value of the first inductor and the third inductor is 275 pH, and the inductance value of the second inductor is 150 pH.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International Patent Application No. PCT/CN2023/108121 with a filing date of Jul. 19, 2023, designating the United States, now pending, and further claims priority to Chinese Patent Application No. 202310803032.4 with a filing date of Jun. 30, 2023. The content of the aforementioned applications, including any intervening amendments thereto, are incorporated herein by reference. TECHNICAL FIELD The disclosure relates to a millimeter-wave low-pass/high-pass reconfigurable filter circuit for signal filtering in different frequency bands through reconfigurable technologies. It is used in microwave and millimeter-wave integrated circuits and belongs to the technical field of filters. BACKGROUND ART The millimeter-wave frequency band, with its advantages of high frequency, wide bandwidth, and abundant spectrum resources, has become a research hotspot for realizing compact, high-speed, and high-capacity wireless communication systems. It holds promising application prospects in many fields such as communications and radar. Meanwhile, as the spectrum resources in low-GHz frequency bands have been extensively utilized and are gradually depleting, the millimeter-wave frequency band has become the preferred choice for high-speed wireless data transmission. Currently, the spectrum for the fifth-generation mobile communication technology (5G) has been classified as two frequency bands, one is the FR1 band (450 MHz-7 GHz), which is a low-frequency band centered around 3.5 GHz, characterized by long transmission distances and strong signal penetration, making it the primary band for 5G; the other is the FR2 millimeter-wave band (24.25˜71 GHz), which features high transmission rates and abundant spectrum resources. Among these, the 2019 World Radiocommunication Conference (WRC) designated 24.25˜29.5 GHz and 37˜43.5 GHz as the two mainstream millimeter-wave bands for 5G. Furthermore, to achieve higher communication capacity, millimeter-wave communication can also utilize multiple frequency bands to expand the communication bandwidth further. Millimeter-wave filters, including low-pass filters, high-pass filters, and band-pass filters, are one of the key modules in millimeter-wave transceiver front-ends. Currently, various millimeter-wave filters operating at different fixed frequency bands have been realized. However, millimeter-wave filters capable of simultaneously performing frequency selection for signals in different bands are very few, and no millimeter-wave filter has been found that can switch between passband and stopband states to filter multiple different frequency bands while possessing stop band suppression characteristics. When future millimeter-wave communication systems operate across multiple frequency bands to achieve greater communication capacity and more flexible networking, if the method of switching between multiple fixed-band millimeter-wave filter circuits is still employed, it would make the communication system very complex and lead to increased cost, power consumption, and size, making it difficult to meet the needs of multi-band wireless communication systems, especially mobile devices. Therefore, developing millimeter-wave filter structures that can operate at different frequency bands will enable hardware circuit reuse, simplify the architecture of communication systems, and simultaneously reduce cost and power consumption. SUMMARY To overcome the deficiencies in the existing research, the disclosure provides a millimeter-wave low-pass/high-pass reconfigurable filter that achieves the interchange of filter passband and stopband in two modes, realizes reconfigurable filtering output across multiple frequency bands, and exhibits low passband loss as well as good image signal suppression in the stopband. A millimeter-wave low-pass/high-pass reconfigurable filter is disclosed, which includes a series-parallel reconfiguration structure, a passband compensation inductor, and a ground-direct connection reconfiguration structure. The series-parallel reconfiguration structure is a parallel resonant network including a first switch, a second switch, a third switch, a first inductor and first capacitor. An input terminal is connected to one end of the first switch and one end of the second switch. The other end of the first switch is connected to one end of 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. The other end of the third switch is connected to the other end of the first inductor. The aforementioned components together constitute the series-parallel reconfiguration structure. The passband compensation inductor includes 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. The other end of the second inducto