CN103594766B - Miniaturization coplanar compact type electromagnetic band gap structure - Google Patents

Abstract

The invention discloses a miniaturized coplanar compact electromagnetic bandgap structure, which is composed of a dielectric substrate and a metal patch with a special structure; the metal patch is attached to the dielectric substrate; it is characterized in that: the metal The patch is composed of four inductive arms and four capacitive arms; one end of the four inductive arms and one end of the four capacitive arms meet and connect at the center, and the other ends of the four inductive arms and the other ends of the four capacitive arms are radially arranged at intervals, and the intersections are in phase The angle between the adjacent inductor arm and capacitor arm is 45 degrees. Since the four inductance arms and four capacitance arms of the present invention are radially arranged at intervals, the angle between the adjacent inductance arms and the capacitance arms at the intersection is 45 degrees, which has a relatively large inductance and capacitance. The invention has a simple structure, can be realized by a single-layer printed circuit board process, has a small plane size and is convenient for integration with wireless communication equipment, and is suitable for improving the electromagnetic characteristics of high-frequency devices such as antennas and filters.

Description

Miniaturized coplanar compact electromagnetic bandgap structure

technical field

The invention relates to an electromagnetic bandgap structure, in particular to a miniaturized coplanar compact electromagnetic bandgap structure which prevents transmission of signals within a specific frequency band range.

Background technique

The EBG structure has bandgap characteristics and isotropic reflection characteristics, and its bandgap characteristics can suppress the surface wave of the microstrip patch antenna. With the development of large-scale integrated circuits and the progress of production technology, people hope to integrate circuits, active devices and radiation elements into a circuit board to facilitate large-scale production and reduce costs. The microstrip patch antenna has the characteristics of easy integration, which makes this design idea feasible. However, the general integrated circuit substrate uses high dielectric constant materials (such as: Si, GaAs and InP), due to the surface wave and dielectric wave mode The radiation efficiency of microstrip patch antennas on these high-permittivity substrates is very low. In some cases, the power loss caused by surface waves accounts for more than 60% of the entire radiated power, which greatly reduces the radiation efficiency of the microstrip patch antenna. In the design process of this microstrip patch antenna, the use of EBG materials can suppress the surface wave and medium wave mode excited by the radiation patch and propagate in the substrate, reduce the loss caused by the surface wave and medium wave mode, and increase the patch antenna Coupling of radiated power into free space increases antenna efficiency. EBG materials can also reduce the sidelobe and backlobe levels generated by surface waves at the edge of the substrate, increase the front-to-back ratio of the antenna, improve the antenna pattern, and increase the antenna gain. In the design process of the array antenna, the use of the EBG structure can reduce the mutual coupling between units and eliminate the scanning blind area of the array antenna. In addition to the function of suppressing the surface wave of the microstrip patch antenna, EBG also has the function of reducing the ground bounce noise (GroundBounceNoise: GBN) of the printed circuit board (Printed Circuit Board: PCB), which can solve the problem of signal integrity in the high-speed design process of the printed circuit board. The problem.

There are many types of electromagnetic bandgap structures, among which the coplanar compact electromagnetic bandgap structure has good high-impedance surface characteristics, in-phase reflection characteristics and surface wave suppression characteristics, and has attracted the attention of many scholars and professionals. With the continuous improvement of miniaturization requirements of communication systems, the miniaturization design of the electromagnetic bandgap structure to improve the electromagnetic characteristics of the system becomes inevitable, and the present invention is designed based on the above-mentioned purpose.

Contents of the invention

The object of the present invention is to provide a miniaturized coplanar compact electromagnetic bandgap structure which is easy to produce and process, has low production cost, and has large capacitance and inductance capacitance.

In order to achieve the above object, the technical solution of the present invention is a miniaturized coplanar compact electromagnetic bandgap structure, which is composed of a dielectric substrate and a metal patch with a special structure; the metal patch is attached to the dielectric substrate; the The metal patch described above is composed of four inductor arms and four capacitor arms; one end of the four inductor arms and one end of the four capacitor arms meet and connect at the center, and the other ends of the four inductor arms and the other ends of the four capacitor arms are radially arranged at intervals, The angle between the adjacent inductance arm and the capacitance arm at the intersection is 45 degrees.

The four inductance arms have the same structural size, but they are mirror images of each other in structure, and the angle between the adjacent inductance arms at the junction is 90 degrees, and each inductance arm is formed by bending a microstrip line with a fixed width.

The four capacitor arms have the same structural size, but they are mirror images of each other in structure. The angle between the adjacent capacitor arms at the intersection is 90 degrees. Each inductor arm is formed by helically winding a microstrip line with a fixed width.

After adopting the above technical scheme, due to the special inductance and capacitance structure of the present invention, larger inductance and capacitance can be generated between the coplanar compact electromagnetic bandgap structure units, reducing the resonant frequency of the electromagnetic bandgap structure, and realizing miniaturization . The invention has a simple structure, can be realized by a single-layer printed circuit board process, has a small plane size and is convenient for integration with wireless communication equipment, and is suitable for improving the electromagnetic characteristics of high-frequency devices such as antennas and filters. The invention has the advantages of simple implementation, mature technology, high degree of automation, low production cost and wide application range.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is a top view of the present invention;

Fig. 2 is a side view of the present invention;

Fig. 3 is the form diagram of 2 * 2 cell arrays of the present invention;

Fig. 4 is the 2 * 4 unit electromagnetic bandgap transmission characteristic curve of the present invention that utilizes the transmission line method to test;

FIG. 5 is a schematic diagram of a 2×4 unit electromagnetic bandgap structure;

Fig. 6 is a schematic diagram of testing by the suspended microstrip line method.

detailed description

As shown in Fig. 1 and Fig. 2, the present invention is a miniaturized coplanar compact electromagnetic bandgap structure. What this structure achieves is the electromagnetic bandgap characteristic in the C-band. It consists of a metal copper patch 1 and a polytetrafluoroethylene microwave dielectric substrate 2 . The metal copper patch 1 is pasted on the upper surface of the polytetrafluoroethylene microwave dielectric substrate 2, and its structure can be realized by using PCB technology. The dielectric substrate 2 has a thickness of 1.5 mm, is a polytetrafluoroethylene microwave dielectric substrate, and has a dielectric constant of 4. The metal copper patch 1 has a thickness of 0.035mm.

The metal copper patch 1 is composed of four inductive arms 11 , 13 , 15 , 17 and four capacitive arms 12 , 14 , 16 , 18 . One end of four inductor arms 11, 13, 15, 17 and one end of four capacitor arms 12, 14, 16, 18 meet and connect at the center, the other end of four inductor arms 11, 13, 15, 17 and four capacitor arms 12, The other ends of 14, 16, and 18 are radially arranged at intervals, that is, around the intersection point, the inductance arm 11, the capacitance arm 12, the inductance arm 13, the capacitance arm 14, the inductance arm 15, the capacitance arm 16, the inductance arm 17, The capacitance arm 18, the angle between the adjacent inductance arm and the capacitance arm at the intersection is 45 degrees.

The four inductance arms have the same structural size, but are mirror images of each other in structure. The angle between adjacent inductor arms at the junction is 90 degrees. Each inductance arm is formed by bending a fixed-width microstrip line to obtain greater inductance.

The four capacitor arms have the same structural size, but are structurally mirror images of each other. The angle between adjacent capacitor arms at the junction is 90 degrees. Each capacitor arm is a single plate of a capacitor made of a fixed-width microstrip helically wound. According to the periodicity of the electromagnetic bandgap structure, the other plate of the capacitor can be formed by a capacitor arm of an adjacent electromagnetic bandgap structure unit. To achieve, the two capacitor arms are spirally wound in parallel, so that a larger capacitance can be obtained in a unit area, and a miniaturized spiral capacitor can be realized. In order to illustrate the structural characteristics of the spiral capacitor formed by the electromagnetic bandgap structure of adjacent units, please refer to FIG. 3 .

As shown in FIG. 3 , in the form of a 2×2 unit array in the present invention, the capacitor arms 10 of four adjacent units together form two sets of spiral capacitors.

By adjusting the arm width of the spiral capacitor arm, the capacitance gap spacing, the broken line inductor arm width, the inductor gap spacing and the number of turns, the equivalent capacitance and equivalent inductance can be changed, so that the bandgap of the coplanar compact electromagnetic bandgap structure The center frequency is set at the preset frequency point. Figure 4 is the transmission characteristic curve of the 2×4 unit electromagnetic bandgap tested by the suspended microstrip line method. It can be seen that there is an obvious bandgap characteristic in the 600MHz bandwidth at the center frequency of 5.35GHz. Among them, Fig. 5 is a schematic diagram of a 2 × 4 unit electromagnetic bandgap structure, and Fig. 6 is a schematic diagram of a suspended microstrip line test, which includes a 2 × 4 unit electromagnetic bandgap structure 61 of the present invention, a 50ohm microstrip line 62, and a supporting medium 63 , SMA seat 64.

Certainly, the present invention can also have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can implement various corresponding deformations according to the present invention, but these corresponding changes and deformations All should belong to the protection scope of the claims of the present invention.

Claims (1)

1. a Miniaturization coplanar compact type electromagnetic band gap structure, it is made up of the metal patch of medium substrate and special construction; Described metal patch is attached on medium substrate; It is characterized in that: described metal patch is made up of four inductance arms and four electric capacity arms; Article four, one end of inductance arm and one end of four electric capacity arms cross in center and are connected, and the other end of the other end of four inductance arms and four electric capacity arms is radially spaced, and between the inductance arm that intersection is adjacent and electric capacity arm, angle is 45 degree;

Four described inductance arm configurations are measure-alike, but mirror image each other in structure, between the inductance arm that intersection is adjacent, angle is 90 degree, and every bar inductance arm is all that the microstrip line of fixed width is bent to form;

Four described electric capacity arm configurations are measure-alike, but mirror image each other in structure, angle 90 degree between the electric capacity arm that intersection is adjacent, every bar electric capacity arm is all that the microstrip line helically coiling of fixed width is formed.