CN110176663A - Circularly polarization microstrip patch antenna - Google Patents

Abstract

A circularly polarized microstrip patch antenna, comprising: a conductive ground plane, a dielectric substrate arranged on the conductive ground plane, a radiation sheet arranged on the top of the dielectric substrate, and several feed feeders arranged on the side walls around the dielectric substrate Probe; the dielectric substrate includes a lower dielectric substrate with a high dielectric constant and an upper dielectric substrate with a low dielectric constant; the radiation sheet is a thin circular metal conductor, and the middle part of the radiation sheet is processed with a symmetrical gear shape Opening; the present invention adopts a gradual folding type side coupling feeding method, the feeding probe is gradually bent, the processing is simple, and it is easy to form a wider bandwidth, the circular polarization performance of the antenna is improved, and the phase center is stable, and the right Two kinds of circular polarization, circular polarization and left-handed, are especially suitable for accurate measurement and guidance system terminal equipment; using two kinds of dielectric substrates with different dielectric constants, the designed product has small size, light weight, and wide gain bandwidth, which can reach 25 %above.

Description

Circularly Polarized Microstrip Patch Antenna

technical field

The invention belongs to the technical field of antennas, and in particular relates to a circularly polarized microstrip patch antenna.

Background technique

As a component used to transmit or receive radio waves, circularly polarized antennas play a vital role in wireless communication systems, especially in satellite communications and aircraft measurement and control equipment.

The current satellite navigation and positioning equipment is widely used in fields such as positioning, measurement, timing, high-precision agriculture and intelligent transportation. In order to obtain high-precision positioning requirements above the decimeter level, navigation equipment generally adopts RTK (real-time dynamic differential method) technology. And axle ratio bandwidth), and more compact size, while processing and manufacturing should be simple. Due to the advantages of small shape, low cost, easy conformality, easy processing and easy realization of circular polarization, microstrip patch antennas are widely used, and the same is true for circularly polarized antennas.

The main problems of current circularly polarized antennas are:

1. Ordinary microstrip antennas generally implement a single-layer medium to achieve a working frequency band. This kind of working bandwidth is relatively narrow, and the working bandwidth is only about 5% z, which cannot be well applied in ultra-wideband (spread spectrum) communication systems. If the bandwidth is increased, it is often necessary to use a medium with a low dielectric constant as the antenna substrate material, and the size of the antenna will increase at this time.

2. Conventional helical antennas have good frequency bandwidth, beam width, symmetric pattern, and wide-angle circular polarization. The disadvantage is that only one polarization mode can be realized. In the case where dual circular polarization is required, it cannot meet the application.

3. Array antenna (or element deformation), frequency bandwidth, symmetric pattern, and wide-angle circular polarization performance are good. The disadvantages are that the beam is not wide enough, the structure is more complicated, and the size is larger.

Traditional microstrip antennas generally implement dual-band by stacking, that is, generally one layer implements a working frequency band, and two layers are superimposed to achieve dual-band. The upper layer generally achieves higher frequency radiation, and the lower layer achieves lower frequency radiation. The radiation patch on the lower layer serves as the floor for the previous patch. This kind of structure feeds more complicated, and the patch on the upper layer often affects the performance of the patch on the lower layer, resulting in a decrease in the performance of the patch on the lower layer. Moreover, the ordinary microstrip antenna has a narrow working bandwidth and cannot cover multiple satellite navigation systems well. If the bandwidth is increased, it is often necessary to use a medium with a low dielectric constant as the antenna substrate material, and the size of the antenna will increase at this time.

Circularly polarized antennas have a greater advantage because there is no polarization mismatch and it is easier to obtain balanced received power with low correlation. A pair of left-handed circularly polarized waves and right-handed circularly polarized waves are cross-polarized to each other. Ideally, a pair of cross-polarized waves are isolated from each other, that is, the LHCP antenna cannot receive the signal of the RHCP incoming wave. ,vice versa. In fact, there is no absolute circular polarization and linear polarization. The endpoint trajectory of the instantaneous electric field vector of any polarized wave is an ellipse. The ratio of the major axis to the minor axis of the ellipse is called the axial ratio AR (Axial Ratio), which is generally used expressed in dB. The axial ratio is an important performance index of the circularly polarized antenna, which represents the purity of the circular polarization. Generally, the bandwidth with the axial ratio not greater than 3dB is defined as the circularly polarized bandwidth of the antenna. It is an important indicator to measure the difference in signal gain of the antenna in different directions.

The characteristic of circularly polarized waves is that the vertical and horizontal components of the electric field are equal in size and 90 degrees out of phase. In general, microstrip antennas are linearly polarized. However, if a special feeding method is used for the microstrip antenna, two degenerate orthogonal modes are excited in the patch, so that the amplitudes are equal and the phases differ by 90 degrees, and circularly polarized waves can be obtained. Circular polarization can be divided into left-handed and right-handed circular polarization according to the direction of rotation of the electric field. The circularly polarized signal will change after reflection. According to the strength of the reflected signal, we can roughly infer whether the signal has been reflected and the number of reflections, and use this as the basis for signal detection, so it is widely used in the field of measurement and control.

Circularly polarized antennas usually have the form of helical antenna, cross element, microstrip antenna, etc. Among them, the disadvantage of helical antenna is that only one polarization mode can be realized. The high profile of the antennas such as the cross array is not conducive to integration into mobile terminal equipment. The microstrip antenna has its unique advantages, such as low profile, light weight, low cost, easy conformal, etc., and it is easy to form left-handed and right-handed antennas at the same time. Two kinds of polarized signals are required in special occasions. However, the working bandwidth of the traditional microstrip antenna is relatively narrow, generally 3%-5%, which cannot be used in spread spectrum communication. Broadening the frequency bandwidth of circularly polarized antennas is the key to improving their practical value, especially in ultra-wideband communications, which can greatly improve anti-interference performance, and is the focus of research to achieve broadband and miniaturization of antennas.

Contents of the invention

The object of the present invention is to provide a circularly polarized microstrip patch antenna with wide working bandwidth, high gain and small size.

Another object of the present invention is to provide a circularly polarized microstrip patch antenna with compact structure and simple feeding.

In order to solve the above technical problems, the present invention discloses a circularly polarized microstrip patch antenna, comprising: a conductive ground plane, a dielectric substrate disposed on the conductive ground plane, a radiation sheet disposed on the top of the dielectric substrate, and a A number of feeding probes on the side walls around the dielectric substrate;

The dielectric substrate includes a lower dielectric substrate with a high dielectric constant and an upper dielectric substrate with a low dielectric constant;

The radiating sheet is a thin sheet-shaped circular metal conductor, and a gear-shaped opening with a symmetrical structure is processed in the middle of the radiating sheet.

Preferably, the dielectric substrate composed of the high-dielectric-constant dielectric substrate and the low-dielectric-constant dielectric substrate is a stepped circular frustum; Feeding, the feeding probe is a stepped metal sheet or a flexible circuit board that gradually widens or narrows from top to bottom.

Preferably, the feeding probe is an orthogonal feeding probe.

Preferably, the conductive ground plane is a PCB board, and the bottom of the feeding probe is insulated and welded to the conductive ground plane.

Preferably, there are two or more symmetrical feeding probes.

Preferably, notches are processed on the low dielectric constant substrate at positions corresponding to the feeding probes.

Preferably, the upper end of the feeding probe extends into the bottom of the gap.

Preferably, the surface of the circularly polarized microstrip patch antenna is processed with several symmetrical and through mounting holes, so that the circularly polarized microstrip patch antenna can be installed and fixed by fasteners.

Preferably, the feeding probes are symmetrically fixed on the outer surface of the high dielectric constant dielectric substrate by welding or gluing.

Preferably, the middle part of the circularly polarized microstrip patch antenna is solid or processed with a circular through hole.

The circularly polarized microstrip patch antenna of the present invention has the following advantages at least:

1. The gradual folding type side coupling feeding method is adopted, which is different from the traditional stacked coaxial feeding microstrip antenna and the unchanged side coupling feeding method. The feeding probe adopts a gradually bent metal wire or a flexible circuit board , the processing is simple, and it is easy to form a wider bandwidth. The circular polarization performance of the antenna is improved, and the phase center is stable, which realizes ultra-wideband. It can realize both right-handed and left-handed circular polarization at the same time, which meets the requirements of dual circularly polarized signal reception. (or launch) application requirements, especially suitable for precise measurement and guidance system terminal equipment.

2. The central part of the antenna can be made into a hollow form, which is convenient for use on special aircraft.

3. Using two dielectric substrates with different dielectric constants, the designed product has small size, light weight, and wide gain bandwidth, which can reach more than 25%.

4. Generally speaking, the thicker the antenna, the wider the bandwidth, and the better the performance; the product of the present invention is easy to form, and it is easy to make a thicker antenna because it does not involve metallized vias and other processes of ordinary microstrip antennas.

5. The radiation piece of the antenna is on the uppermost layer of the dielectric substrate alone, which is convenient to process, and by adjusting the outer diameter, inner diameter, sawtooth length and width of the radiation piece, the working frequency of the antenna can be fine-tuned, which is convenient for industrial processing. Better fault-tolerant performance improves product pass rate and reduces production cost.

6. By adjusting the material dielectric constant and thickness of the high dielectric constant dielectric substrate and the low dielectric constant dielectric substrate in the dielectric substrate, different operating frequencies, gains and operating bandwidths can be obtained, which is convenient for industrial processing.

7. The setting of the notch enhances the fixing effect on the low dielectric constant dielectric substrate; when the glue is potted, it provides a channel to facilitate the flow of glue.

8. The dielectric substrate is a stepped round platform, which is more resistant to shock and vibration after potting.

Description of drawings

FIG. 1 is a schematic structural diagram of a circularly polarized microstrip patch antenna.

FIG. 2 is a top view of the circularly polarized microstrip patch antenna in FIG. 1 .

FIG. 3 is a schematic structural diagram of the feeding probe in FIG. 1 .

Fig. 4 is a test diagram of antenna gain bandwidth of a circularly polarized microstrip patch antenna.

Fig. 5 is an antenna axial ratio test diagram of a circularly polarized microstrip patch antenna.

Fig. 6 is a test diagram of the center frequency beam width of a circularly polarized microstrip patch antenna.

Fig. 7 is a circuit diagram of a circularly polarized microstrip patch antenna with four feeding probes.

Fig. 8 is a circuit diagram of a circularly polarized microstrip patch antenna with two feeding probes.

The labels in the figure are: 1-conductive ground plane, 2-high dielectric constant dielectric substrate, 3-low dielectric constant dielectric substrate, 4-radiating sheet, 5-feeding probe, 6-circular through hole, 7 - notches, 8 - gear-like openings, 9 - mounting holes.

Detailed ways

The present invention will be further described in detail through the examples below, so that those skilled in the art can implement it with reference to the description.

It should be understood that terms such as "having", "comprising" and "including" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

Example 1

As shown in Figures 1-3, a circularly polarized microstrip patch antenna includes: a conductive ground plane 1, a dielectric substrate disposed on the conductive ground plane, a radiation sheet 4 disposed on the top of the dielectric substrate, and a Several feeding probes 5 on the side walls around the dielectric substrate;

The dielectric substrate includes a lower dielectric substrate 2 with a high dielectric constant and an upper dielectric substrate 3 with a low dielectric constant; by adjusting the dielectric constants and thicknesses of different materials, different operating frequencies, gains and operating bandwidths can be obtained.

The radiation piece 4 is a thin circular metal conductor, and a gear-shaped opening 8 with a symmetrical structure is processed in the middle of the radiation piece for receiving or transmitting signals. In Fig. 2, the outer diameter D1, inner diameter D2, serrated length L1, and width W1 of the radiator are adjusted and matched, and the operating frequency of the radiator can be fine-tuned within a certain range.

The dielectric substrate composed of the high-dielectric-constant dielectric substrate and the low-dielectric-constant dielectric substrate is a stepped circular truncated; the feeding probe adopts a gradually folded side-coupling feeding method to feed the radiation sheet, so The feeding probe is a stepped metal sheet or a flexible circuit board that gradually widens or narrows from top to bottom. In Fig. 3, JW1 is the width of the upper part of the feeding probe, JW2 is the width of the middle part of the feeding probe, and JW3 is the width of the lower part of the feeding probe. In this embodiment, the three parameters of JW1, JW2 and JW3 decrease in turn.

The feeding probe is an orthogonal feeding probe.

The conductive ground plane is a PCB board, and the bottom of the feeding probe is insulated and welded to the conductive ground plane.

There are four symmetrical feeding probes.

Notches 7 are processed on the low dielectric constant dielectric substrate at positions corresponding to the feeding probes. This setting is mainly used in special occasions to facilitate the flow of glue during glue potting.

The upper end of the feeding probe extends into the bottom of the notch. This setting can well fix the low dielectric constant dielectric substrate, and when the structure of the stepped circular platform is potted, it is more resistant to shock and vibration.

The surface of the circularly polarized microstrip patch antenna is processed with four symmetrical and through mounting holes 9, so that the circularly polarized microstrip patch antenna can be installed and fixed by fasteners.

The feeding probes are symmetrically fixed on the outer surface of the high dielectric constant dielectric substrate by welding or glueing.

The middle part of the circularly polarized microstrip patch antenna is a circular through hole 6, which is convenient for use on special aircraft.

Example 2

FIG. 4 shows a test diagram of the antenna gain bandwidth of the circularly polarized microstrip patch antenna in Embodiment 1. As shown in FIG.

FIG. 5 shows an antenna axial ratio test diagram of the circularly polarized microstrip patch antenna in Embodiment 1. As shown in FIG.

FIG. 6 shows a test diagram of the center frequency beam width of the circularly polarized microstrip patch antenna in Embodiment 1.

It can be seen that the circularly polarized antenna device in Embodiment 1 has the characteristics of large axial ratio bandwidth, wide working bandwidth, and stable phase center.

Example 3

As shown in Figure 7, 4 orthogonal feeding probes are used, and every two adjacent ones undergo signal phase shifting, and after combining, good left-handed and right-handed circularly polarized signal outputs are obtained. (Hybrid is a coupler with a phase shift of 90 degrees).

With four feeding probes, the loss of the feeding circuit is large, but the circular polarization performance is good, and the antenna is symmetrical, so that the phase center is stable.

Example 4

As shown in Figure 8, two orthogonal feeding probes can also be used, and the adjacent signals can be combined to obtain good left-handed and right-handed circularly polarized signals:

2 feeding probes, the loss of the feeding circuit is small, so that a higher gain can be obtained.

Two or more feeding probes can be selected for different application scenarios.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and embodiments shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (10)

1. a kind of circularly polarization microstrip patch antenna characterized by comprising conductive earthing plane is set in conductive earthing plane Dielectric substrate, the radiation fin at the top of dielectric substrate and several feed probes set on dielectric substrate surrounding side wall；

The dielectric substrate includes the high dielectric constant dielectric substrate of lower layer and the medium with low dielectric constant substrate on upper layer；

The radiation fin is a laminar circular metal conductor, and the gear-like of a symmetrical configuration is machined in the middle part of the radiation fin Opening.

2. circularly polarization microstrip patch antenna as described in claim 1, which is characterized in that the high dielectric constant dielectric substrate and The dielectric substrate of medium with low dielectric constant substrate composition is ladder-like rotary table；The feed probes use gradual change folded form side coupling Close feeding classification radiation fin is fed, the feed probes be gradually broaden or narrow from top to bottom, stair-stepping metal Thin slice or flexible circuit board.

3. circularly polarization microstrip patch antenna as claimed in claim 2, which is characterized in that the feed probes are orthogonal feed spy Needle.

4. circularly polarization microstrip patch antenna as claimed in claim 3, which is characterized in that the conductive earthing plane is pcb board, The bottom of the feed probes is welded and fixed with conductive earthing planar insulative.

5. the circularly polarization microstrip patch antenna as described in claim 1-4 any one, which is characterized in that the feed probes have It is symmetrical two or more.

6. circularly polarization microstrip patch antenna as claimed in claim 5, which is characterized in that on the medium with low dielectric constant substrate Position processing corresponding with feed probes is jagged.

7. circularly polarization microstrip patch antenna as claimed in claim 6, which is characterized in that the feed probes upper end is protruded into described Indentations bottom.

8. circularly polarization microstrip patch antenna as claimed in claim 7, which is characterized in that the circularly polarization microstrip patch antenna table Face is machined with several symmetrical and perforation mounting hole, makes circularly polarization microstrip patch antenna that fastener can be used and carries out installation fixation.

9. circularly polarization microstrip patch antenna as claimed in claim 8, which is characterized in that the feed probes welding or gluing pair Title is fixed on high dielectric constant dielectric substrate outer surface.

10. circularly polarization microstrip patch antenna as claimed in claim 9, which is characterized in that the circularly polarization microstrip patch antenna Middle part is solid or is machined with circular through hole.