CN112216937A

CN112216937A - Faraday rotary switch

Info

Publication number: CN112216937A
Application number: CN202011388257.0A
Authority: CN
Inventors: 蒋运石; 闫欢; 冯楠轩; 杨勤; 田珺宏; 张远
Original assignee: CETC 9 Research Institute
Current assignee: CETC 9 Research Institute
Priority date: 2020-12-02
Filing date: 2020-12-02
Publication date: 2021-01-12
Anticipated expiration: 2040-12-02
Also published as: CN112216937B

Abstract

The invention discloses a Faraday rotary switch, which mainly comprises two orthogonal mode couplers and a Faraday rotator controlled by a circuit, wherein the Faraday rotator consists of a four-ridge square waveguide, matching ceramic positioned in the four-ridge square waveguide, ferrite and a coil wound on the ferrite, when the coil is electrified, a uniform magnetic field along the length direction of the ferrite can be formed, and when the coil is electrified reversely, the magnetic field is reversed; when the Faraday rotator is electrified, the Faraday rotator can rotate a signal by 45 degrees along the axial direction of the four-ridge square waveguide. The invention provides a novel ferrite switch structure, which utilizes a Faraday rotator to realize the nonreciprocal function of a device, the working frequency of the device in the Faraday rotator is irrelevant to the magnetic moment of the ferrite, the ferrite with lower magnetic moment can be taken, the working frequency band of the ferrite switch is improved, and the working frequency band of a product can reach a Q wave band.

Description

Faraday rotary switch

Technical Field

The invention relates to a switch, in particular to a Faraday rotary switch.

Background

Microwave ferrite devices have been widely used in the electronic technology fields such as microwave communication, radar, microwave energy, etc. In order to realize the polarization mode of the microwave signal or the fast switching between channels, the microwave ferrite switch has the advantage of no alternatives. Currently, three types of mechanical switches, semiconductor active switches and ferrite switches are commonly used as microwave switches. Compared with an electromechanical switch and an electromechanical assembly, the ferrite switch has the advantages of high speed, long service life and no abrasion, so that the reliability is high; compared with a semiconductor switch, the ferrite switch has the advantages of low switching-on loss, high switching-off isolation and large power bearing capacity. Because the microwave ferrite switch has the advantages of low loss, long service life, high reliability and the like, the microwave ferrite switch is widely applied to modern radars and modern communication systems, and is particularly suitable for satellite-borne, airborne, high-frequency-band microwave and millimeter-wave occasions.

The prior ferrite switch usually adopts a junction structure, and for the junction type ferrite switch, the saturation magnetization of gyromagnetic ferrite material needs to satisfy the formula of' 4πM_s＝P·2πf/γ”。

In the formula: m_sIs the saturation magnetization in units of (A/m); p is normalized saturated magnetic moment and is dimensionless;fis the center frequency in (Hz);γ2.21X 10 as gyromagnetic ratio of electron spin⁵rad · m/(S · A). In the low-field working mode, the value range of P is generally 0.5-0.7. It can be seen from the formula that the operating frequency of the junction type ferrite switch is in a direct proportion relation with the magnetic moment of the ferrite, the required magnetic moment is about 10000guass calculated by the central frequency of 50GHz according to the formula, but the highest magnetic moment of the existing ferrite material is about 5000 guass at present, so that the operating frequency of the junction type ferrite switch commonly used at present is difficult to expand to a high frequency band, and the problems of narrow operating bandwidth and small power capacity exist in the prior art.

Disclosure of Invention

The object of the present invention is to provide a faraday rotary switch which solves the above problems, and can extend the operating frequency of a ferrite switch to a high frequency band, and has a wider relative bandwidth and a larger power capacity.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a faraday rotary switch, characterized in that: the orthogonal mode coupler comprises a first input end, a second input end and an output end, the two orthogonal mode couplers are coaxially arranged with the four-ridge square waveguide, the output ends are respectively connected with the two ends of the four-ridge square waveguide, one orthogonal mode coupler is opposite to the four-ridge square waveguide, and the other orthogonal mode coupler rotates 45 degrees along the axis;

the four side surfaces of the four-ridge square waveguide are respectively provided with a ridge along the length direction, the middle part of each ridge is provided with a rectangular annular ferrite, the ferrite comprises two long sides and two short sides, one long side is inserted into the ridge and is bonded with the ridge, the other long side is positioned outside the four-ridge square waveguide and is wound with a coil, the two short sides are positioned at the part inside the ridge and are bonded with matching ceramics, the matching ceramics are used for impedance matching and are arranged along the length direction of the ridge, when the coil is electrified, each coil forms a uniform magnetic field along the length direction of the ferrite, 4 magnetic fields form an integral magnetic field, and when the coil is electrified reversely, the magnetic field is reversed;

the four-ridge square waveguide, the matching ceramic, the ferrite and the magnetic field form a Faraday rotator, and when the Faraday rotator is electrified, a signal can be rotated by 45 degrees along the axial direction of the four-ridge square waveguide.

Preferably, the method comprises the following steps: the matching ceramics at the two short sides of the ferrite are symmetrically arranged, one end close to the ferrite is large, the other end is small, and the whole body is in a wedge shape or a step shape.

According to the invention, the ferrite is wound by the coil at the part outside the four-ridge square waveguide, when the coil is electrified, the magnetic circuit enters the four-ridge square waveguide along the ferrite, a uniform magnetic field along the length direction of the ferrite is formed in the four-ridge square waveguide, and the phase shifting function is realized at the part inside the four-ridge square waveguide.

The electromagnetic wave can be composed of two plane circular polarized waves, the polarization rotation directions of the two plane circular polarized waves are opposite, namely, left-hand circular polarized waves and right-hand circular polarized waves, in the ferrite medium under longitudinal magnetization, the magnetic conductivities of the two plane circular polarized waves are respectively expressed as scalar quantities, and the corresponding effective magnetic conductivities of the left-hand circular polarized waves and the right-hand circular polarized waves in the ferrite are different. Therefore, the propagation constants of the two circularly polarized waves are different, and the resultant linear polarization direction deviates from an angle after the two waves propagate for a certain distance, which is called the faraday rotation angle. The invention organically combines the four-ridge square waveguide, the matching ceramic, the ferrite and the coil together to form the Faraday rotator. After passing through the Faraday rotator formed by the invention, the signal can rotate 45 degrees along the axial direction of the four-ridge square waveguide.

In the invention: after a signal input by the orthogonal mode coupler at one end passes through the faraday rotator, the polarization direction is rotated by 45 degrees, because the position of the second orthogonal mode coupler is rotated by 45 degrees relative to the first orthogonal mode coupler, the included angle between the two first input ends is 45 degrees, the included angle between the two second input ends is 45 degrees, then the two orthogonal mode couplers are respectively positioned at the left end and the right end, the first input end, the second input end, the first input end and the second input end at the left end and the right end are marked as a port 1, a port 2, a port 3 and a port 4 in sequence, then a signal at the port 1 is output from the port 3, a signal at the port 2 is output from the port 4, if the current direction is changed, a signal at the port 1 is output from the port 4, and a signal at the port 2 is output from the port 3. Therefore, after the 2 port is not loaded, the signal of the 1 port can be selected to be output from the 3 port or the 4 port by adjusting the current direction, and the switching function is achieved. And the switch also has an anti-signal reflection function, because when the forward path is from 1 port to 3 ports, the signal reflected by the 3 ports can be absorbed by the 2 ports, namely the load, and can not be directly transmitted to the transmitter of the 1 port.

Compared with the prior art, the invention has the advantages that:

(1) the invention provides a novel ferrite switch structure, which organically combines a four-ridge square waveguide, matching ceramic, ferrite and a coil together to form a Faraday rotator structure, and combines two orthogonal mode couplers which rotate 45 degrees mutually to form the novel ferrite switch structure. The bandwidth is increased, the relative bandwidth of the existing ferrite switch is narrow, generally less than 10%, and the relative bandwidth of the invention can reach 12%.

(2) The working frequency band is improved. The invention utilizes the Faraday rotator to realize the nonreciprocal function of the device, the magnetic moment of the ferrite in the Faraday rotator can not be influenced by frequency, the ferrite with lower magnetic moment can be taken, and the invention is different from the traditional junction type ferrite switch which is limited by the magnetic moment of the existing ferrite material, so that the working frequency band is difficult to develop at high frequency in the past. The invention utilizes the Faraday rotator to improve the working frequency band, so that the working frequency band of the product can reach the Q wave band.

(3) The power capacity is improved. The invention adopts the over-mode square waveguide, overcomes the defect of smaller power capacity of the existing ferrite switch, and has larger power capacity.

The Faraday rotary switch working in the Q wave band designed by the invention only uses ferrite material with 3000 glass magnetic moment to realize the bandwidth of 5GHz, the relative bandwidth of more than 12 percent, the port standing wave of less than or equal to 1.2 and the isolation of more than or equal to 20 dB.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a cross-sectional view of FIG. 1 taken along its length;

FIG. 3 is an enlarged view of a portion A of FIG. 2;

FIG. 4 is a cross-sectional view of FIG. 1;

FIG. 5 is a schematic view of the structure of the internal ferrite and matching ceramic of the present invention;

FIG. 6 is a schematic diagram of a signal rotated 45;

fig. 7 is a S-parameter graph of example 3.

In the figure: 1. a four-ridge square waveguide; 2. an orthogonal mode coupler; 3. a ferrite; 4. a coil; 5. a first input terminal; 6. a second input terminal; 7. an output end; 8. matching ceramics; 9. a ridge.

Detailed Description

The invention will be further explained with reference to the drawings.

Example 1: referring to fig. 1 to 6, a faraday rotary switch includes a four-ridge square waveguide 1 and orthogonal mode couplers 2 located at two ends of the four-ridge square waveguide, where the orthogonal mode coupler 2 includes a first input end 5, a second input end 6, and an output end 7, the two orthogonal mode couplers 2 are coaxially disposed with the four-ridge square waveguide 1, the output end 7 is respectively connected with two ends of the four-ridge square waveguide 1, one orthogonal mode coupler 2 is directly opposite to the four-ridge square waveguide 1, and the other orthogonal mode coupler 2 rotates 45 ° along an axis;

four sides of the four-ridge square waveguide 1 are respectively provided with a ridge 9 along the length direction, the middle part of each ridge 9 is provided with a rectangular annular ferrite 3, the ferrite 3 comprises two long sides and two short sides, one long side is inserted into the ridge 9 and is bonded with the ridge 9, the other long side is positioned outside the four-ridge square waveguide 1 and is wound with a coil 4, the two short sides are positioned at the part inside the ridge 9 and are bonded with matching ceramics 8, the matching ceramics 8 are used for impedance matching and are arranged along the length direction of the ridge 9, when the coil 4 is electrified, each coil 4 forms a uniform magnetic field along the length direction of the

ferrite

3, 4 magnetic fields form an integral magnetic field, and when the coil is electrified reversely, the magnetic fields are reversed;

the four-ridge square waveguide 1, the matching ceramic 8, the ferrite 3 and the magnetic field form a Faraday rotator, and when the Faraday rotator is electrified, signals can be rotated by 45 degrees along the axial direction of the four-ridge square waveguide 1.

In this embodiment, the matching ceramics 8 on the two short sides of the ferrite 3 are symmetrically arranged, and one end close to the ferrite 3 is large, and the other end is small, and the whole body is in a wedge shape. But not limited thereto, it may be provided in a stepped type. The structure of the matching ceramic 8 can be seen in fig. 5.

Example 2: referring to fig. 1 to 5, on the basis of embodiment 1, we design an X-band faraday rotary switch according to the method of the present invention, the bandwidth is 1.4GHz, the relative bandwidth is greater than 16%, the port standing wave is less than or equal to 1.2, the isolation between orthogonal modes is greater than or equal to 20dB, and the isolation of the faraday rotator is greater than or equal to 20 dB.

In this embodiment, the magnetic moment of the ferrite 3 ring is 820guass, the length is 80mm, the length of the matched ceramic 8 is 40mm, the size of the four-ridge square waveguide 1 is 20mm × 20mm, the length is 190mm, and the input and output are BJ100 standard waveguide ports.

Example 3: referring to fig. 1 to 7, on the basis of embodiment 1, we design a Q-band faraday rotary switch according to the method of the present invention, the bandwidth is 5GHz, the relative bandwidth is greater than 12%, the port standing wave is less than or equal to 1.2, the isolation between orthogonal modes is greater than or equal to 20dB, and the isolation of the faraday rotator is greater than or equal to 20 dB.

In the present embodiment, the ferrite 3 ring has a magnetic moment of about 3000 gusss and a length of 20mm, the length of the matching ceramic 8 is 9mm, and the size of the four-ridge waveguide is 4.2mm × 4.2mm and 40mm long. The input and the output are BJ400 standard waveguide ports.

Referring to fig. 7, in the graph of S parameter of the product, S11 is return loss, S21 is isolation between 1 and 2 ports, S31 is transmission loss, and S41 is isolation between 1 and 4 ports. S11 is less than-20 dB, S21 and S41 are both greater than 20dB, and S31 is less than 1dB, which shows that the device has excellent electrical property and can completely realize the function of a switch.

Comparing the existing ferrite switch products on the market with the products of the invention, the following performance comparison table is obtained:

and the following performance comparison table is obtained by comparing the comparison product with the product of the invention:

table 1: performance comparison table

Reference is made to comparative products: 3mm ferrite high speed switch simulation design Yi Jie hong; the substrate integrated waveguide ferrite switch between Chen Yu.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A faraday rotary switch, characterized in that: the orthogonal mode coupler comprises a first input end, a second input end and an output end, the two orthogonal mode couplers are coaxially arranged with the four-ridge square waveguide, the output ends are respectively connected with the two ends of the four-ridge square waveguide, one orthogonal mode coupler is opposite to the four-ridge square waveguide, and the other orthogonal mode coupler rotates 45 degrees along the axis;

2. A faraday rotary switch according to claim 1, characterized in that: the matching ceramics at the two short sides of the ferrite are symmetrically arranged, one end close to the ferrite is large, the other end is small, and the whole body is in a wedge shape or a step shape.