CN-122026068-A - Non-reciprocal full duplex filter antenna based on substrate integrated waveguide and space-time modulation

CN122026068ACN 122026068 ACN122026068 ACN 122026068ACN-122026068-A

Abstract

The invention belongs to the technical field of wireless communication, and particularly relates to a non-reciprocal full duplex filter antenna based on a substrate integrated waveguide and space-time modulation, which ensures efficient transmission of a receiving path and a transmitting path and port isolation from an antenna port to the transmitting port transmission path and from the transmitting port to the receiving port transmission path for realizing full duplex communication. The invention firstly builds the nonreciprocal circulator based on the space-time modulation technology, realizes the directional transmission characteristics of antenna port, receiving port and transmitting port, and simultaneously obtains the high isolation of the antenna port, transmitting port and transmitting port, and receiving port. And secondly, the filter characteristic of the substrate integrated waveguide is utilized to integrate band-pass filter response in the transmission paths of the three ports, so that low-loss transmission in the working frequency band and effective suppression of out-of-band signals are realized. Finally, integrating a slot antenna structure at an antenna port to complete the space radiation and receiving functions of signals. Through the design, the device realizes the integrated integration of three functions of circulation, filtering and radiation.

Inventors

YANG TAO
Wu Jingtuo
NING YUHANG

Assignees

电子科技大学

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (6)

1. The nonreciprocal full duplex filter antenna based on the substrate integrated waveguide and the space-time modulation is characterized by comprising a substrate integrated waveguide cavity, three radio frequency ports, namely an antenna port Ant, a receiving port Rx and a transmitting port Tx, three modulation ports, namely a first modulation port, a second modulation port and a third modulation port, three second-order low-pass filters, namely a first second-order low-pass filter, a second-order low-pass filter and a third second-order low-pass filter, two varactors, namely a first varactor C 2 and a second varactor C3, three coupling varactors, namely a first coupling varactor C12, a second coupling varactor C23 and a third coupling varactor C13, three matching capacitors, namely a first matching capacitor Cm1, a second matching capacitor Cm2 and a third matching capacitor Cm3, and three inductors, namely a first inductor L1, a second inductor L2 and a third inductor L3, wherein: The top metal of the substrate integrated waveguide cavity is etched with a slot antenna, the slot antenna forms the physical realization of an antenna port Ant, three sector-shaped substrate integrated waveguide resonators, namely a first resonator R1, a second resonator R2 and a third resonator R3, are arranged in the substrate integrated waveguide cavity in an annular mode, and form a main body frame of a ring coupling structure and jointly realize a filtering function so as to form a resonant structure; the antenna port Ant is directly coupled and connected with the first resonator R1, the input end of the first second-order low-pass filter is connected with the first modulation port, the output end of the first second-order low-pass filter is connected with the first resonator R1, one end of the first matching capacitor Cm1 is connected with a connecting node between the antenna port Ant and the first resonator R1, and the other end of the first matching capacitor Cm1 is grounded; The transmitting port Tx is coupled and connected with the third resonator R3 through the second varactor C3, the input end of the third second-order low-pass filter is connected with the third modulation port, the output end of the third second-order low-pass filter is connected with the third resonator R3, one end of the third matching capacitor Cm3 is connected with a connecting node between the transmitting port Tx and the third resonator R3, and the other end of the third matching capacitor Cm3 is grounded; The receiving port Rx is coupled and connected with the second resonator R2 through the first varactor C 2 , the input end of the second-order low-pass filter is connected with the second modulation port, the output end of the second-order low-pass filter is connected with the second resonator R2, one end of the second matching capacitor Cm2 is connected with a connecting node between the receiving port Rx and the second resonator R2, and the other end of the second matching capacitor Cm2 is grounded, the second inductor L2 is connected in series on a signal transmission path of the receiving port Rx, and the receiving port Rx realizes impedance matching with an external circuit through the second matching capacitor Cm2, thereby forming a receiving path; The first coupling varactor C12 is bridged between the first resonator R1 and the second resonator R2, the second coupling varactor C23 is bridged between the second resonator R2 and the third resonator R3, and the third coupling varactor C13 is bridged between the first resonator R1 and the third resonator R3, and the three components together form a ring coupling structure.
2. The non-reciprocal full duplex filter antenna based on substrate integrated waveguide and space-time modulation according to claim 1, wherein the three sector-shaped substrate integrated waveguide resonators are sector-shaped cavities with a central angle of 120 degrees and are arranged in a central symmetrical ring shape in the substrate integrated waveguide cavities.
3. The non-reciprocal full duplex filtering antenna based on substrate integrated waveguide and space-time modulation according to claim 1 or 2, wherein electromagnetic coupling is formed between adjacent sector substrate integrated waveguide resonators through coupling gaps, and a first coupling varactor C12, a second coupling varactor C23 and a third coupling varactor C13 are respectively connected across corresponding adjacent resonators, for cooperatively controlling coupling strength between the resonators.
4. The non-reciprocal full duplex filtering antenna based on substrate integrated waveguide and space-time modulation according to claim 1, wherein the first matching capacitor Cm1, the second matching capacitor Cm2 and the third matching capacitor Cm3 are all parallel capacitors to ground, i.e. one end of each matching capacitor is connected to a connection node of a corresponding radio frequency port and a corresponding resonator, and the other end is grounded.
5. The non-reciprocal full-duplex filter antenna based on substrate integrated waveguide and space-time modulation according to claim 1, wherein the first inductor L1, the second inductor L2 and the third inductor L3 respectively form an electromagnetic coupling structure for introducing transmission zero together with the input structure of the corresponding radio frequency port so as to improve the out-of-band rejection characteristic of the non-reciprocal full-duplex filter antenna.
6. The non-reciprocal full duplex filtering antenna based on substrate integrated waveguide and space-time modulation according to claim 1, wherein the first resonator R1, the second resonator R2 and the third resonator R3 are excited to generate space-time modulation by the modulated signals with the same frequency, the same amplitude and the progressive phase loaded by the first modulation port, the second modulation port and the third modulation port, thereby realizing the non-reciprocal transmission of radio frequency signals from the transmitting port Tx to the antenna port Ant and from the antenna port Ant to the receiving port Rx and simultaneously realizing the isolation of the antenna port Ant to the transmitting port Tx and the transmitting port Tx to the receiving port Rx.

Description

Non-reciprocal full duplex filter antenna based on substrate integrated waveguide and space-time modulation Technical Field The invention belongs to the technical field of wireless communication, and particularly relates to a non-reciprocal full duplex filter antenna based on a substrate integrated waveguide and space-time modulation. Background Full duplex radio frequency front end systems in modern wireless communication systems have received attention because they allow for simultaneous transmission and reception of transmitter and receiver signals, thereby widening the communication spectrum. Wherein the filter, circulator and antenna are key components of the full duplex radio frequency front end. However, the conventional cascade device architecture makes the system structure huge, and the addition of a complex matching circuit prevents the modern wireless communication system from developing to miniaturization, reconfigurability and multiple modes. And the co-design method of the functional device effectively solves the problem. Which allows multiple different functions to be integrated in a single device, not only maintaining the integrity of the functions, but also greatly reducing the size. At present, although a filter and an isolator or a circulator are combined and designed, and a space-time modulation technology is mostly adopted, research on integrated design of the filter, the circulator and an antenna has never been proposed. The scheme effectively solves the problems of single working mode and huge size of the current wireless system, and becomes an effective path for the development of the wireless system in future. However, research on designing filters, circulators and antennas integrally has never been proposed. Disclosure of Invention The invention aims at a nonreciprocal full duplex filter antenna based on a substrate integrated waveguide and space-time modulation, so as to solve the problems of single working mode and huge size of the existing wireless system and realize the functional integrated design of circulation, filtering and radiation. In order to achieve the above purpose, the invention adopts the following technical scheme: A non-reciprocal full duplex filter antenna based on substrate integrated waveguide and space-time modulation comprises a substrate integrated waveguide cavity; the three radio frequency ports are an antenna port, a receiving port and a transmitting port respectively, three modulation ports are a first modulation port, a second modulation port and a third modulation port, three second-order low-pass filters are a first second-order low-pass filter, a second-order low-pass filter and a third second-order low-pass filter, two varactors are a first varactor diode and a second varactor diode, three coupling varactors are a first coupling varactor diode, a second coupling varactor diode and a third coupling varactor diode, three matching capacitors are a first matching capacitor, a second matching capacitor and a third matching capacitor, three inductors are a first inductor, a second inductor and a third inductor, wherein: A slot antenna is etched on the top metal of the substrate integrated waveguide cavity, and the slot antenna forms physical realization of an antenna port; three sector-shaped substrate integrated waveguide resonators, namely a first resonator, a second resonator and a third resonator, are arranged in the substrate integrated waveguide cavity in an annular mode, and form a main body frame of an annular coupling structure and jointly realize a filtering function so as to form a resonant structure; The antenna port is directly coupled with the first resonator, the input end of the first second-order low-pass filter is connected with the first modulation port, and the output end of the first second-order low-pass filter is connected with the first resonator; The transmitting port is coupled with a third resonator through a second varactor, the input end of the third second-order low-pass filter is connected with a third modulation port, the output end of the third second-order low-pass filter is connected with the third resonator, one end of a third matching capacitor is connected with a connecting node between the transmitting port and the third resonator, and the other end of the third matching capacitor is grounded; The receiving port is coupled and connected with the second resonator through the first varactor C 2, the input end of the second-order low-pass filter is connected with the second modulation port, the output end of the second-order low-pass filter is connected with the second resonator, one end of the second matching capacitor is connected with a connecting node between the receiving port and the second resonator, and the other end of the second matching capacitor is grounded; The first coupling varactor is connected between the first resonator and the second resonator in a bridging way, the second coupling varactor is connec