CN108306085A - Upper and lower composite structure microstrip circulator - Google Patents

Abstract

The invention discloses a kind of composite structure microstrip circulators up and down, belong to microwave device field, include permanent magnet successively from top to bottom（5）, dieelctric sheet（4）And bottom plate（2）, it is characterised in that：The dieelctric sheet（4）And bottom plate（2）Between be provided with low magnetic moment ferrite substrate（10）, the low magnetic moment ferrite substrate（10）Microstrip circuit is arranged in upper surface（3）, the bottom plate（2）On be embedded with high magnetic moment ferrite substrate（11）, the high magnetic moment ferrite substrate（11）With low magnetic moment ferrite substrate（10）It is adjacent；The present invention effectively reduces the low field loss that high magnetic moment Ferrite Material unsaturation magnetic band comes, and improves the normalization magnetic moment P of microstrip circulator, has expanded the bandwidth of operation of circulator, bandwidth of operation is 7GHz 13GHz, the dB of transmission loss≤0.4, port standing wave≤1.4, isolation >=15.

Description

Up and down compound structure microstrip circulator

technical field

The invention relates to the field of microwave components, in particular to a microstrip circulator with an upper and lower composite structure.

Background technique

Circulator is an important basic device in microwave engineering, which is widely used in various civil and military equipment such as civil communication, microwave measurement, radar, communication, electronic countermeasures, aerospace and so on. The circulator is mainly used in the equipment to realize the sharing of antenna transmission and reception, inter-stage isolation and other issues. Due to its small size, light weight, and easy integration, the microstrip circulator plays an important role in the development of contemporary radar communication systems. The current largest application is mainly the active phased array TR module. With the active phased array With the development of radar, there is an urgent demand for microstrip circulators with wider frequency band and larger power capacity.

The traditional microstrip circulator is shown in Figure 1. The ferrite material is used as the microstrip substrate, that is, the ferrite substrate 1. The upper and lower sides of the ferrite substrate 1 are metallized by sputtering equipment, and the upper surface is a microstrip circuit. The lower surface is the ground, and the lower surface is welded to the base plate, and the base plate and the lower surface of the ferrite form a common ground. Under the magnetization of the permanent magnet, the ferrite substrate 1 realizes circular transmission of signals: the port A7 is transmitted to the port B8, the port B8 is transmitted to the port C9, and the port C9 is transmitted to the port A7.

The role of the dielectric sheet 4 in the figure is to adjust the magnetic field strength and reduce the influence of the permanent magnet on the circular microstrip circuit, and the function of the compensation sheet 6 is to adjust the performance parameters at the temperature of the circulator.

The technical problems and defects of the traditional power divider are mainly reflected in the following aspects:

1. For the microstrip circulator in the low-field working mode, the selection of the saturation magnetization of the gyromagnetic ferrite substrate directly affects the working bandwidth of the circulator.

The relationship between the saturation magnetization 4πMs of the gyromagnetic ferrite material and the working frequency f is as follows:

4πMs=P·2πf/γ

γ is the gyromagnetic ratio of the electron spin, which is equal to 2.21×10 ⁵ rad·m/(S·A)

P is the normalized saturation magnetic moment, dimensionless, low-field working mode, and the value of P generally ranges from 0.3 to 0.7;

Within the value range, the larger the value of P, the wider the bandwidth that the circulator can achieve. That is to say, the use of a ferrite substrate with a high magnetic moment is beneficial to realize the broadband of the device.

According to the transmission theory of the microstrip circulator, only the ferrite under the center junction of the microstrip circuit needs to be saturated and magnetized to optimally realize the circulatory performance, and the ferrite substrate outside the center junction is only used as a microstrip substrate medium , it is not easy to realize the performance of the device after magnetization.

However, in actual product work, the ferrite substrate is a whole substrate, and it is impossible for an external magnetic field to accurately saturate and magnetize the central junction region without magnetizing the ferrite outside the central junction. The unsaturated magnetization of the ferrite substrate outside the central junction brings about

Low field loss directly affects the working bandwidth of the product, especially when the value of the normalized magnetic moment P is larger, the higher the saturation magnetization of the material selected, the greater the low field loss will be.

The traditional microstrip circulator structure cannot expand the bandwidth by using ferrite materials with high saturation magnetization due to structural limitations. The bandwidth can only achieve about 40%, such as 8GHz-12GHz microstrip circulator.

Contents of the invention

The object of the present invention is to provide a microstrip circulator with an up-and-down composite structure to solve the above problems.

In order to achieve the above object, the technical solution adopted by the present invention is as follows: a microstrip circulator with an up-and-down composite structure comprises a permanent magnet, a dielectric sheet and a bottom plate sequentially from top to bottom, and a A low magnetic moment ferrite substrate, a microstrip circuit is arranged on the upper surface of the low magnetic moment ferrite substrate, a high magnetic moment ferrite substrate is embedded on the bottom plate, and the high magnetic moment ferrite substrate is connected to the low magnetic moment ferrite substrate. The magnetic moment ferrite substrates are adjacent.

The invention digs a groove in the center of the bottom plate, embeds a ferrite substrate with high magnetic moment, and welds the ferrite substrate with low magnetic moment above the bottom plate with the bottom plate to form an upper and lower composite ferrite substrate structure; the permanent magnet is composed of the same bottom plate A high magnetic moment ferrite substrate can be well magnetized by an applied bias magnetic field; through the above method, the present invention effectively reduces the low field loss caused by the unsaturated magnetization of the high magnetic moment ferrite material, and improves the The normalized magnetic moment P and P value of the microstrip circulator can be increased to more than 0.5, which expands the working bandwidth of the circulator.

As a preferred technical solution: the saturation magnetization of the low magnetic moment ferrite substrate is 1800 Gauss.

As a preferred technical solution: the saturation magnetization of the high magnetic moment ferrite substrate is 2500Gauss.

Using the above-mentioned low magnetic moment ferrite substrate and high magnetic moment ferrite substrate with saturation magnetization, the product P value can reach 0.7.

As mentioned above, whether the saturation magnetization of the ferrite substrate belongs to high magnetic moment ferrite or low magnetic moment ferrite corresponds to its working frequency. According to the relationship between the saturation magnetization 4πMs of the gyromagnetic ferrite material and the working frequency f, the following formula is as follows:

4πMs=P·2πf/γ

γ is the gyromagnetic ratio of the electron spin, which is equal to 2.21×10 ⁵ rad·m/(S·A)

P is the normalized saturation magnetic moment, dimensionless, low-field working mode, and the value of P generally ranges from 0.3 to 0.7;

In this field, generally, when the value of P is lower than 0.5, it is regarded as a ferrite with low magnetic moment, and when the value of P is higher than 0.5, it is regarded as a ferrite with high magnetic moment. For low-field devices, the smaller the P value, the narrower the circulator's operating bandwidth, but the smaller the in-band loss; the larger the P value, the wider the circulator's operating bandwidth, and relatively larger in-band loss. (Magnetic moment = saturation magnetization)

For traditional low-field circulators, if the P value is set below 0.5, the bandwidth can only be achieved by 40%. If the P value is set above 0.5 in the traditional structure, the low field loss caused by the unsaturated magnetization of high magnetic moment ferrite The bandwidth of the device is directly deteriorated, so that the bandwidth of the device cannot be effectively expanded.

The invention innovatively proposes to compound a high magnetic moment circular ferrite substrate under the low magnetic moment ferrite substrate, the normalized saturation magnetic moment P is taken above 0.5, and the external bias magnetic field can correct the regular high magnetic moment The circular ferrite substrate is fully saturated and magnetized, which eliminates the generation of low field loss. Through performance simulation and product testing, it is proved that this structural scheme can effectively expand the bandwidth of the device.

Compared with the prior art, the advantage of the present invention is that: on the basis of the traditional microstrip circulator, the present invention composites a ferrite substrate with high magnetic moment under the ferrite substrate by means of embedding, and the ferrite substrate with high magnetic moment Concentrated below the central junction, the external bias magnetic field can uniformly saturate and magnetize the high-moment ferrite substrate, effectively reducing the low field loss caused by the unsaturated magnetization of high-magnetic-moment ferrite materials, and the transmission loss is ≤ 0.4 dB, improve the normalized magnetic moment P of the microstrip circulator, expand the working bandwidth of the circulator, the working bandwidth is 7GHz-13GHz, the port standing wave is ≤1.4, and the isolation is ≥15, realizing the broadband matching of the microstrip circulator .

Description of drawings

Fig. 1 is the structural representation of prior art of the present invention;

Fig. 2 is the structural representation of the embodiment of the present invention;

Fig. 3 is the circulator loss simulation result figure of the embodiment of the present invention;

Fig. 4 is the circulator isolation simulation result figure of the embodiment of the present invention;

FIG. 5 is a graph showing the simulation result of a standing wave of a circulator according to an embodiment of the present invention.

In the figure: 1. Ferrite substrate; 2. Bottom plate; 3. Microstrip circuit; 4. Dielectric sheet; 5. Permanent magnet; 6. Compensation sheet; 7. Port A; 8. Port B; 9. Port C; 10. Low magnetic moment ferrite substrate; 11. High magnetic moment ferrite substrate.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

Example:

Referring to Fig. 2, a microstrip circulator with an up-and-down composite structure includes a permanent magnet 5, a dielectric sheet 4 and a bottom plate 2 from top to bottom, and a low magnetic moment ferrite is arranged between the dielectric sheet 4 and the bottom plate 2 Substrate 10, the saturation magnetization of the low magnetic moment ferrite substrate 10 is 1800Gauss, the upper surface of the low magnetic moment ferrite substrate 10 is provided with a microstrip circuit 3, and the base plate 2 is embedded with a high magnetic moment ferrite An oxygen substrate 11, the saturation magnetization of the high magnetic moment ferrite substrate 11 is 2500Gauss, and the high magnetic moment ferrite substrate 11 is adjacent to the low magnetic moment ferrite substrate 10;

In this embodiment, a high magnetic moment ferrite substrate 11 is embedded by digging a groove in the center of the bottom plate 2, and the low magnetic moment ferrite substrate 10 above the bottom plate 2 is welded with the bottom plate 2 to form an upper and lower composite ferrite substrate structure; The applied bias magnetic field formed by the permanent magnet 5 and the bottom plate 2 can perform good magnetization on the high magnetic moment ferrite substrate 11;

The microstrip circulator obtained in this embodiment has a working bandwidth of 7 GHz-13 GHz, a transmission loss of 0.4 dB, a normalized magnetic moment P of 0.7, a port standing wave of 1.4, and an isolation of 15 dB.

For the circulator of this embodiment, the loss simulation result is shown in FIG. 3 , the isolation simulation result is shown in FIG. 4 , and the standing wave simulation result is shown in FIG. 5 .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (3)

1. a kind of composite structure microstrip circulator up and down includes permanent magnet successively from top to bottom（5）, dieelctric sheet（4）And bottom plate （2）, it is characterised in that：The dieelctric sheet（4）And bottom plate（2）Between be provided with low magnetic moment ferrite substrate（10）, the low magnetic Square ferrite substrate（10）Microstrip circuit is arranged in upper surface（3）, the bottom plate（2）On be embedded with high magnetic moment ferrite substrate （11）, the high magnetic moment ferrite substrate（11）With low magnetic moment ferrite substrate（10）It is adjacent.

2. composite structure microstrip circulator up and down according to claim 1, it is characterised in that：The low magnetic moment ferrite Substrate（10）Saturation magnetization be 1800Gauss.

3. composite structure microstrip circulator up and down according to claim 1, it is characterised in that：The high magnetic moment ferrite Substrate（11）Saturation magnetization be 2500Gauss.