CN103474767A - Four-frequency plane microstrip antenna with miniaturized microwave absorption structure - Google Patents

Abstract

The four-frequency planar microstrip antenna with a miniaturized wave-absorbing structure solves the problems in the prior art that the microstrip antenna is large in volume, poor in gathering and collection, and unsuitable for multiple frequency bands. The antenna includes: a dielectric substrate; a feeder set on the upper surface of the dielectric substrate and used to receive electromagnetic waves; a four-branch radiation unit connected to the feeder and used to radiate electromagnetic waves, set on the upper surface of the dielectric substrate and two left and right relative to the feeder Side symmetrical grounding plate; the feeder and the four-branch radiating unit are within the outline formed by the inner edge of the grounding plate, the inner edges of the grounding plate on the left and right sides of the four-branch radiating unit are symmetrical trapezoids, and the grounding plate on the lower side of the four-branch radiating unit The inner edges are two trapezoids that are symmetrical to the feeder line, the inner edges of the grounding plate on the upper side of the four-branch radiation unit are multiple continuous triangles, and the inner edges of the grounding plates on the left and right sides of the feeder line are parallel straight lines. The microstrip antenna of the present invention has small volume and concentrated energy, and can realize the omnidirectional radiation of the antenna to four frequency bands.

Description

Four-band Planar Microstrip Antenna with Miniaturized Absorbing Structure

technical field

The invention relates to the technical field of wireless communication, in particular to a four-frequency planar microstrip antenna with a miniaturized wave-absorbing structure.

Background technique

The microstrip antenna (microstrip antenna) is on a thin dielectric substrate, one side is attached with a thin metal layer as a ground plane, and the other side is made of a metal patch of a certain shape by photolithography and etching, using a microstrip line or a coaxial probe An antenna formed by feeding a patch. Microstrip antennas have the advantages of miniaturization, easy integration, and good directivity, and have been widely used in wireless communication technology.

Commonly used communication frequency bands for wireless communication systems are RFID systems (2.4GHz, 5.8GHz), IEEE802.11b/g (2.4GHz), IEEE802.11a (5.2GHz), WIMAX (3.3-3.7GHz) and WLAN (2.45GHz, 5.15- 5.85GHz).

The earliest microstrip antennas are only suitable for one communication frequency band, such as a 2.4GHz miniaturized microstrip antenna (Wireless Communication Technology, 2009.4, 30-32) and a new 2.4GHz band-loaded patch antenna design (Journal of Radio Wave Science , December 2004, Issue 6, Volume 19, 730-734), but with the rapid development of short-distance wireless technology and wireless local area network technology, from the perspective of spectrum resource allocation, the original 802.11b (2.402-2.480 The bandwidth and transmission rate in the GHz) protocol are very limited and cannot meet the requirements of data communication. Therefore, the 802.11a (5.155.35GHz) protocol, which is compatible with higher frequencies and has more abundant spectrum resources, has emerged. In order to further meet the application requirements, a multi-mode wireless network compatible with IEEE802.11a and IEEE802.11b has become a research trend, but FLAN (wireless local area network) with 802.11a and 802.11b2 versions will require a dual-band radio Transmitters or two single-band radio transmitters are used in the 2.4GHz frequency band and the 5.2GHz frequency band respectively, but when using two single-band radio transmitters, it will inevitably occupy more physical space for communication equipment, which is different from the small size of mobile terminals. At this time, the radio transmitter is required to use an antenna capable of dual-frequency operation, so it is particularly important to develop an antenna that can realize dual-frequency operation on a wireless LAN. For example, the design of a dual-band microstrip slot antenna working at 2.4GHz/5.2GHz (Devices and Applications, 2011, Volume 35, Issue 11, 43-46), this document designs a small dual-band antenna that can work on a FLAN network Microstrip antenna, the resonant frequencies are 2.4GHz and 5.2GHz respectively, and the working bandwidth includes two frequency bands of 2.402-2.483GHz and 5.15-5.35GHz. Although this method realizes the dual-frequency operation of the antenna, the volume of the antenna is still relatively large, the collection and collection of stray electromagnetic waves is poor, and the radiation efficiency of electromagnetic waves in specific frequency bands is limited.

In addition, in the prior art, there is no planar microstrip antenna with high integration, small size, and capable of simultaneously covering multiple frequency bands of systems such as RFID, WLAN, WIMAX, and C-band.

Contents of the invention

In order to solve the technical problems in the prior art that the microstrip antenna is large in size, poor in gathering and collection, limited in radiation efficiency to electromagnetic waves in a specific frequency band, and unsuitable for multiple frequency bands, the present invention provides a four-frequency planar microstrip with a miniaturized wave-absorbing structure antenna.

The miniaturized wave-absorbing structure quad-frequency planar microstrip antenna of the present invention includes:

Dielectric substrate;

A feeder set on the upper surface of the dielectric substrate and used for receiving electromagnetic waves;

a four-branch radiating unit connected to the feeder and used for radiating electromagnetic waves;

a ground plate set on the upper surface of the dielectric substrate and symmetrical to the left and right sides of the feeder;

The feeder line and the four-branch radiating unit are within the outline formed by the inner edge of the grounding plate, the inner edges of the grounding plates on the left and right sides of the four-branch radiating unit are symmetrical trapezoids, and the inner edges of the grounding plate on the lower side of the four-branch radiating unit are Two trapezoids that are symmetrical to the feeder line, the inner edge of the ground plate on the upper side of the four-branch radiation unit is a plurality of continuous triangles, and the inner edges of the ground plate on the left and right sides of the feeder line are two parallel straight lines;

The four-branch radiation unit is adjacent to the upper base of the trapezoid, and the connection between the inner edges of the grounding plates on the left and right sides of the four-branch radiation unit and the inner edges of the grounding plates on the upper and lower sides of the four-branch radiation unit is an acute angle;

The upper ends of the two parallel straight lines are respectively connected to two symmetrical trapezoids on the inner edge of the grounding plate on the lower side of the four-twig radiation unit.

Further, the upper end of the four-branch radiation unit is four resonant branches matching electromagnetic waves of different wavelength bands, and the lower end of the four-branch radiation unit is an inverted trapezoidal structure.

Further, the plurality of continuous triangles are a plurality of continuous inverted triangles.

Further, the triangle is an isosceles triangle.

Further, the distance between the ground plate and the feeder is 0.5mm.

Further, the dielectric substrate is an FR-4 dielectric substrate with a relative permittivity (εr) of 4.4, and a loss tangent of 0.02.

Description of working principle: Electromagnetic waves propagate forward in the antenna along the feeder line and the grounding plate. When passing through the four branch radiation units, the antenna produces omnidirectional radiation to the electromagnetic waves corresponding to the frequency bands of the above four resonant branches with different lengths. By adopting The grounding plate with different shapes of wrapped absorbing structure effectively changes the direction of the surface current when the electromagnetic wave radiates forward, collects and gathers the electromagnetic wave, and strengthens the signal of the electromagnetic wave in the required radiation frequency band. By effectively adjusting the four The length of the resonant stub can realize the resonant effect of the antenna on electromagnetic waves in different frequency bands, thereby realizing the RFID system (2.4GHz, 5.8GHz), IEEE802.11b/g (2.4GHz), IEEE802.11a (5.2GHz), WIMAX (3.3 -3.7GHz) and WLAN (2.45GHz, 5.15-5.85GHz) and other civil communication systems produce effective radiation antennas.

The beneficial effects of the present invention are:

(1) The antenna of the present invention uses a coplanar waveguide structure for feeding, which realizes the miniaturization and planar design of the antenna, and designs the ground plate as a wave-absorbing structure. On the basis of ensuring the miniaturization of the antenna, the antenna The surface current realizes the gathering and collection of stray electromagnetic waves, thereby enhancing the radiation efficiency of the antenna for electromagnetic waves in specific frequency bands;

(2) The antenna of the present invention can realize the resonant action of the antenna to electromagnetic waves of different frequency bands by effectively adjusting the lengths of the four resonant branches under the premise of ensuring omnidirectional radiation of the antenna, such as being able to respond to RFID systems (2.4GHz, 5.8GHz) , IEEE802.11b/g (2.4GHz), IEEE802.11a (5.2GHz), WIMAX (3.3-3.7GHz) and WLAN (2.45GHz, 5.15-5.85GHz) and other communication systems all produce effective radiation. Under the premise of integration, the high performance and multi-function of the antenna are realized.

Description of drawings

Fig. 1 is the top view of miniaturized wave-absorbing structure four-frequency planar microstrip antenna of the present invention;

Fig. 2 is the front view of the miniaturized wave-absorbing structure four-frequency planar microstrip antenna in Fig. 1;

Fig. 3 is the parameter schematic diagram of the standing wave ratio bandwidth of the miniaturized wave-absorbing structure four-frequency planar microstrip antenna of the present invention;

Fig. 4 is a schematic diagram of the peak gain parameters of the miniaturized wave-absorbing structure four-frequency planar microstrip antenna of the present invention;

Fig. 5 is the radiation pattern diagram of the miniaturized wave-absorbing structure four-frequency planar microstrip antenna of the present invention at 2.4GHz;

Fig. 6 is the radiation pattern diagram of the miniaturized wave-absorbing structure four-frequency planar microstrip antenna of the present invention at 4GHz;

Fig. 7 is the radiation pattern of the four-frequency planar microstrip antenna of miniaturized wave-absorbing structure of the present invention at 5 GHz;

Fig. 8 is a radiation pattern at 6 GHz of the quad-band planar microstrip antenna with a miniaturized absorbing structure of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figures 1 and 2, the four-frequency planar microstrip antenna with a miniaturized wave-absorbing structure of the present invention uses a coplanar waveguide structure for feeding, and realizes the design concept of miniaturization and planarization of the antenna. It is mainly composed of a dielectric substrate 1, The feeding line 2, the grounding plate 3 and the four-branch radiating unit 4 are formed, wherein the feeding line 2, the grounding plate 3 and the radiating unit 4 are all conductively arranged on the dielectric substrate 1, and are on the same plane and have the same thickness of each part; The feeder 2 is a conductive metal feeder, the lower end of which is connected to a coaxial cable for receiving electromagnetic waves; the four-branch radiation unit 4 is a conductive metal radiation unit, and the upper end is four resonance branches that match electromagnetic waves of different wavelengths and frequency bands: The first resonant branch 4-1, the second resonant branch 4-2, the third resonant branch 4-3 and the fourth resonant branch 4-4 have an inverted trapezoidal structure at the lower end, and the upper bottom edge of the inverted trapezoidal structure is connected to the coaxial cable The central conductor is indirectly connected to the feeder 2 for radiating electromagnetic waves; the grounding plate 3 is a conductive metal grounding plate, the feeder 2 and the four-twig radiation unit 4 are within the outline formed by the inner edge of the grounding plate 3, the feeder 2 and four-branch radiating unit 4 are not in contact with the grounding plate 3, the distance between the feeder 2 and the grounding plate 3 is 0.5mm, and the grounding plate 3 adopts a wave-absorbing structure, that is, the grounding plates on the left and right sides of the four-branch radiating unit 4 The inner edge of 3 is a symmetrical trapezoid, the inner edge of the grounding plate 3 on the lower side of the four-twig radiation unit 4 is two symmetrical trapezoids with respect to the feeder 2, and the inner edge of the grounding plate 3 on the upper side of the four-twig radiation unit 4 is A plurality of continuous triangles, the above four trapezoids and the four-branch radiation unit 4 are adjacent to the upper base of the trapezoid, and the inner edges of the ground plate 3 on the left and right sides of the four-branch radiation unit 4 are connected to the upper and lower sides of the four-branch radiation unit 4 The connection of the inner edge of the ground plate 3 on the side is an acute angle, the inner edges of the ground plate 3 on the left and right sides of the feeder 2 are parallel straight lines, and the upper ends of the parallel lines are respectively connected to the inner edges of the ground plate 3 on the lower side of the four-branch radiation unit 4. The edges of the two symmetrical trapezoids are connected.

In the above structure, the inverted trapezoidal structure at the lower end of the four-branch radiating unit 4 is conducive to the forward radiation of electromagnetic waves; the gap between the feeder 2 and the grounding plate 3 mainly acts as a guiding electromagnetic wave, and the parallel straight line at the inner edge of the grounding plate 3 can effectively The surface electromagnetic wave is guided to the four-twig metal radiation unit 4 .

When the above-mentioned multiple continuous triangles are multiple continuous inverted triangles, especially isosceles triangles, the microelectric antenna of the present invention can achieve better effects.

In the antenna of the present invention, the dielectric substrate 1 is an FR-4 type dielectric substrate (glass cloth substrate) with a relative permittivity of 4.4, a loss tangent of 0.02, and a thickness of 1mm. This type of dielectric substrate has low cost and is easy to compare with ordinary Printed circuit board integration.

The antenna of the present invention is 30 mm long, 44 mm wide, and 1 mm thick. Using thermal transfer printing, the copper layer on the surface of the dielectric substrate 1 that has been tested for dielectric constant is polished and profiled, and the structural model of the antenna is printed, and the vernier caliper determines Antenna size, cut the dielectric substrate 1 according to the size, put the printed antenna into the corrosion solution, and after about 5 minutes of vibration corrosion, the unnecessary copper layer on the antenna surface is removed, and the miniaturized wave-absorbing structure four-frequency planar microstrip is completed. antenna.

As shown in Figure 3, in the four frequency bands of 2.3GHz-2.5GHz, 3.6GHz-3.9GHz, 4.6GHz-5.0GHz and 5.3GHz-5.9GHz, the return loss parameters of the antenna of the present invention are all less than -10dB, which meets the requirements of the antenna Therefore, the electromagnetic waves of these four frequency bands can effectively radiate electromagnetic waves to the external space through the antenna of the present invention.

As shown in Figure 4, in 2.3GHz-2.5GHz, 3.6GHz-3.9GHz, 4.6GHz-5.0GHz and 5.3GHz-5.9GHz four effective bandwidth frequency ranges, the gain of the antenna of the present invention is stable between 0dB-3dB It further shows that the antenna can effectively and stably radiate the electromagnetic waves of the above four frequency bands to the outside.

As shown in Figure 5, Figure 6, Figure 7 and Figure 8, the antenna of the present invention presents in the four operating frequency bands of 2.3GHz-2.5GHz, 3.6GHz-3.9GHz, 4.6GHz-5.0GHz and 5.3GHz-5.9GHz Omnidirectional radiation, as shown in Figure 5, in the 2.3GHz-2.5GHz frequency band, the radiation reaches the strongest when the angle is 0° and 180°, as shown in Figure 6, in the 3.6GHz-3.9GHz frequency band, when the angle is 0° The radiation reaches the strongest when the angle is 0° and 180°, as shown in Figure 7. In the 4.6GHz-5.0GHz frequency band, the radiation reaches the strongest when the angle is 0° and 180°, as shown in Figure 8, the 5.3GHz-5.9GHz frequency band The radiation reaches the strongest when the angle is 0° and 180°, and the gain pattern of the antenna is approximately circular in the above four typical frequency bands, indicating that the antenna has good and stable omnidirectional radiation in these four frequency bands Features, can be applied to a variety of civil wireless communication technology fields, and has the advantages of high integration and low cost.

Claims (6)

1. The four-frequency planar microstrip antenna with miniaturized wave-absorbing structure is characterized in that, comprising: Dielectric substrate (1); a feeder (2) set on the upper surface of the dielectric substrate (1) and used for receiving electromagnetic waves; A four-branch radiating unit (4) connected to the feeder (2) and used for radiating electromagnetic waves; a grounding plate (3) set on the upper surface of the dielectric substrate (1) and symmetrical to the left and right sides of the feeder line (2); The feeder (2) and the four-twig radiating unit (4) are within the outline formed by the inner edge of the grounding plate (3), and the inner edges of the grounding plate (3) on the left and right sides of the four-twig radiating unit (4) are symmetrical Trapezoidal, the inner edge of the grounding plate (3) on the lower side of the four-twig radiation unit (4) is two trapezoids symmetrical to the feeder (2), and the grounding plate (3) on the upper side of the four-twig radiation unit (4) The inner edges are a plurality of continuous triangles, and the inner edges of the grounding plates (3) on the left and right sides of the feeder (2) are parallel straight lines; The four-branch radiation unit (4) is adjacent to the upper base of the trapezoid, and the inner edges of the grounding plates (3) on the left and right sides of the four-branch radiation unit (4) are connected to the upper and lower sides of the four-branch radiation unit (4). The junction of the inner edges of the floor (3) is an acute angle; The upper ends of the parallel straight lines are respectively connected with two symmetrical trapezoids on the inner edge of the grounding plate (3) on the lower side of the four-twig radiation unit (4). 2. The miniaturized wave-absorbing structure four-frequency planar microstrip antenna according to claim 1, wherein the upper end of the four-branch radiation unit (4) is four resonant branches that match electromagnetic waves of different wavelength bands, and the four-branch radiation The lower end of the unit (4) is an inverted trapezoidal structure. 3. The miniaturized wave-absorbing structure quad-frequency planar microstrip antenna according to claim 1, wherein the plurality of continuous triangles are a plurality of continuous inverted triangles. 4. The four-frequency planar microstrip antenna with miniaturized wave-absorbing structure according to claim 3, wherein the triangle is an isosceles triangle. 5. The miniaturized wave-absorbing structure four-frequency planar microstrip antenna according to claim 1, characterized in that the distance between the feeder (2) and the ground plate (3) is 0.5mm. 6. The miniaturized wave-absorbing structure four-frequency planar microstrip antenna according to claim 1, wherein the dielectric substrate (1) is an FR-4 dielectric substrate with a relative permittivity of 4.4, and a loss tangent of 0.02 .

Images