Small microstrip double frequency antenna
Technical field
What the present invention relates to is a kind of dual-band antenna that is used for wireless communication technology field, especially a kind of small microstrip double frequency antenna.
Background technology
Wireless communication technology develops very soon, cell phone, global positioning system (GPS), synthetic aperture radar (SAR), satellite communication, personal communication fields such as (GSM900/DCS1800) all need simple, the easy antenna of conformal two-band of light weight, low profile, manufacturing.Microstrip antenna is little with its volume, and is in light weight, low section, can be conformal with carrier, be easy to make, cost is low, be easy to be integrated into single module, be convenient to realize that advantages such as circular polarization, dual polarization and two-band obtain increasingly extensive concern and application with active device and circuit.
In the prior art, in order to make the microstrip antenna two-frequency operation, can realize by following several method usually: (one) adopts many mount technologies; (2) adopt the slit loading technique; (3) adopt the lamped element loading technique.But adopt many mount technologies and lamped element loading technique all can make the structure of antenna become complicated, the slit loads as another kind of load mode, though can on the single layer microstrip antenna, realize double frequency, but this method need be determined the shape and size in slit by a large amount of emulation experiments, therefore requires a great deal of time and resource.
Find through literature search prior art, in May, 2003, people such as Zheng-weiDu was at IEEETRANSACTIONS ON VEHICULAR TECHNOLOGY (vehicle-mounted technology), the 52nd volume is delivered " ACompact Planar Inverted-F Antenna With a PBG-Type Ground Plane for MobileCommunications (a kind of be used for mobile communication be the inverse-F antenna of ground plane with PBG) " the 3rd phase, in this article, proposed to replace traditional metal ground plane to design inverse-F antenna with the ground plane of pbg structure, regulate the corresponding work frequency band by the thickness that changes medium, but the inverse-F antenna structure more complicated of this pbg structure, it needs a bigger ground plane simultaneously, therefore is unfavorable for the miniaturization Design of antenna.Also find in the retrieval, Chinese patent application number 03104907.9, patent name is: the double L-shaped dual-band antenna of plane formula, patent publication No. CN1525597A, this dual-band antenna comprises the radiant body of a L type that is printed on dielectric medium substrate one side, and is printed on second radiant body that dielectric medium substrate opposite side is stretched out by ground plane and is inverted L shape.Be to stretch out by microstrip line and co-planar waveguide mode and ground plane to form radiant body respectively in this patent, and realize different operating frequencies with the L shaped microstrip line of the quarter-wave length of operating frequency separately respectively according to different operating frequencies.But the dual-band antenna of Shi Xianing requires between these two radiant bodies certain interval to be arranged by this way, therefore makes the size of whole dual-band antenna be subjected to certain restriction.
Summary of the invention
The objective of the invention is to overcome the deficiencies in the prior art and defective, a kind of small microstrip double frequency antenna is provided, make it can realize utilizing single microband paste to realize the requirement of two-frequency operation, simultaneously this dual-band antenna have that volume is less relatively, structure simple and clear, it is simple to make, easy conformal advantage.
The present invention is achieved by the following technical solutions, the present invention includes: antenna element, feed port, dielectric-slab and ground unit, the non-homogeneous microband paste of antenna element for calculating according to the back scattering method, be positioned at the front of dielectric-slab, the core and the antenna element of feed port join, and ground unit is the part that is positioned at the dielectric-slab back side.
Described antenna element is positioned at the dielectric-slab front, and the physical dimension of antenna element is calculated according to Z-S back scattering method, is non-uniform Distribution.
Described antenna element is equated by electrical length on the whole and non-homogeneous microband paste cascade that width does not wait forms, and its overall electrical length is to be 0.3 times of wavelength of benchmark with 1GHz.
Described antenna element and ground unit are conductor, and the outer conductor of ground unit and feed port is connected.
Described dielectric-slab is the low-k material.
The present invention and prior art contrast, and its effect is actively with tangible.The non-homogeneous micro-strip paster antenna that utilizes inverse scattering method to design has less relatively size, structure is simple and clear, it is conformal to be easy to, and the frequency requirement that has covered portable terminal effectively is GSM wave band (0.89GHz-0.96GHz) and DCS wave band (1.71GHz-1.88GHz).
Description of drawings
Fig. 1 is the Facad structure schematic diagram of a kind of dual-band antenna of the present invention
Fig. 2 is the side-looking structural representation of a kind of dual-band antenna of the present invention
Fig. 3 is the reverse side structural representation of a kind of dual-band antenna of the present invention
Fig. 4 is the frequency characteristic figure of a kind of dual-band antenna emulation of the present invention
Embodiment
As Fig. 1, Fig. 2 and shown in Figure 3, the present invention includes: antenna element 1, feed port 3, dielectric-slab 2 and ground unit 4, the non-homogeneous microband paste of antenna element 1 for calculating according to the back scattering method, be positioned at the front of dielectric-slab 2, the core of feed port 3 and antenna element 1 join, and ground unit 4 is the parts that are positioned at dielectric-slab 2 back sides.
Described antenna element 1 is positioned at dielectric-slab 2 fronts, the physical dimension of entire antenna is to calculate according to the Z-S back scattering method after existing the improvement, be non-uniform Distribution, the present invention that compares with traditional Z-S method has mainly adopted first order difference equation to make computational efficiency improve, and has improved computational accuracy.
Described antenna element 1 is equated by electrical length on the whole and non-homogeneous microband paste cascade that width does not wait forms, and its overall electrical length is to be 0.3 times of wavelength of benchmark with 1GHz.
Described antenna element 1 and ground unit 4 are conductor, and ground unit 4 is connected with the outer conductor of feed port 3.The present invention adds outside signal source by feed port 3, and pumping signal can be gone out to space radiation all around by antenna element 1.
Described dielectric-slab 2 is the low-k material.
As shown in Figure 4, frequency characteristic of the present invention is a return wave loss parameter.Wherein abscissa is represented frequency variable, and unit is GHz; Ordinate is represented the amplitude variable, and unit is dB.The working band of microstrip double frequency antenna of the present invention is respectively GSM wave band (0.89GHz-0.96GHz) and DCS wave band (1.71GHz-1.88GHz), and the amplitude of return wave loss parameter in these two wave bands is less than-10dB.