CN201323233Y - Internal dual-frequency antenna - Google Patents

Abstract

The utility model relates to a built-in dual-frequency antenna. The existing products have large volume, low reliability and low electrical performance index. The utility model comprises a sheet-shaped L-shaped excitation microstrip, a parasitic microstrip, a short-circuit strip and a sheet-shaped rectangular antenna floor. The excitation microstrip, the parasitic microstrip, the short circuit strip and the antenna floor are an integral structure of metal sheets. One end of the short-circuit strip is connected to the antenna floor, and the other end is connected to the excitation microstrip. The excitation microstrip is connected to the antenna floor through the short-circuit strip. One end of the parasitic microstrip is connected to the antenna floor and is spaced and parallel to the excitation microstrip. The antenna floor The tail is turned inward. The utility model has compact structure and low cost, and can effectively work in two frequency bands of 1880-1920MHz and 2010-2025MHz used by TD-SCDMA. It more evenly reflects the requirements of terminal antenna miniaturization, simple structure and dual-frequency operation.

Description

A built-in dual-band antenna

technical field

The utility model belongs to the technical field of microstrip antennas and relates to a built-in dual-frequency antenna applied to a TD-SCDMA standard mobile communication terminal.

Background technique

As an international 3G standard with independent intellectual property rights proposed by China for the first time, TD-SCDMA has received great attention from the government, operators and manufacturers. With the joint efforts of all parties, TD-SCDMA technology has been established in the Trial networks have been established in many cities across the country. With the application of the TD-SCDMA standard, there are new requirements for the terminal antenna used in the standard. Today, academia and engineering circles have made a lot of explorations and efforts in the fields of antenna miniaturization, dual-band and even multi-band, and one of the main directions is to design more types of small multi-band antennas for 3G terminals.

For mobile communication terminal manufacturers, the antenna feeder part, especially the antenna part of the mobile communication terminal, is affected by the structure, size, installation position of electronic components and the performance of the housing material of the mobile communication terminal due to its performance and structural size. Influenced by the slow progress of technology, the antenna integration level of mobile communication terminals is still relatively low and the price is relatively high, which restricts the further development of mobile communication terminal technology.

On the other hand, with the strengthening of people's awareness of the harm of electromagnetic radiation from mobile communication terminals to the human body, users are increasingly demanding that mobile communication terminals must have low electromagnetic radiation indicators without degrading the performance of existing mobile communication terminal equipment. . At present, antenna forms suitable for direct integration on mobile terminals mainly include the following two types: 1. external antennas; 2. built-in antennas.

Most of the external antennas are telescopic, such as whip antennas and helical antennas, which are widely used in mobile terminals. The external antenna has many disadvantages: it cannot be integrated into the printed circuit board or the equipment casing, which increases the overall size (especially the telescopic type); it is easy to break and bend; the antenna has a high SAR value and is not easy to shield, and the human body has a greater impact on the performance of the antenna Large; there is only one polarization characteristic, and the field performance is poor near the human body. It is not easy to achieve precise control and repeatability in the processing of helical antennas, and a matching circuit is required, which increases the cost and loss; the retractable external antenna also has a physical limit to the number of times the antenna can be retracted; when the telescopic antenna is in a certain intermediate position, the antenna Not electrically connected to the telephone; external antennas usually require an internal diversity antenna to account for attenuation.

Correspondingly, built-in antennas have some special advantages. It can not only make the shape design of the mobile communication terminal more flexible and smaller in size, but also achieve low specific signal absorption ratio (SAR) and high peak gain, and the built-in antenna can also realize the antenna in a relatively small volume array. It can be predicted that the built-in antenna will be the first choice for the antenna of the mobile communication terminal in the future.

However, the existing planar built-in antennas are all designed and manufactured in a two-dimensional plane. Since there are only two design degrees of freedom, there are the following disadvantages:

1. The volume is too large to be used for miniaturized mobile communication terminal equipment (such as mobile phones) with strict size requirements;

2. The installation of the built-in antenna requires a support frame or needs to be connected to the housing, which not only increases the production cost, but also reduces the reliability and maintainability;

3. The electrical performance index is low, for example, the in-band return loss is relatively high, which affects the antenna efficiency and increases the power consumption of the terminal equipment.

Contents of the invention

The purpose of the utility model is to provide a built-in antenna for a mobile communication terminal with a three-dimensional spatial structure suitable for the TD-SCDMA standard, aiming at the deficiencies of the prior art.

The utility model comprises a sheet-shaped excitation microstrip, a parasitic microstrip, a short circuit strip and an antenna floor.

The excitation microstrip is L-shaped, including the sheet-like long strip excitation short microstrip and the excitation long microstrip whose long axes are perpendicular to each other. The plane where the excitation short microstrip is located is perpendicular to the plane where the excitation long microstrip is located, and the excitation short microstrip The plane where it is located is perpendicular to the plane where the antenna floor is located, and the plane where the excited long microstrip is located is parallel to the plane where the antenna floor is located. The long axis of the excitation short microstrip is perpendicular to the long axis of the antenna floor, and the long axis of the excitation long microstrip is parallel to the long axis of the antenna floor. The tail end of the excitation short microstrip is connected with the head end of the excitation long microstrip.

The parasitic microstrip is L-shaped, including a long strip of parasitic short microstrip and a parasitic long microstrip whose major axes are perpendicular to each other. The parasitic short microstrip and the parasitic long microstrip are in the same plane and are perpendicular to the plane where the antenna floor is located. , the long axis of the parasitic short microstrip is perpendicular to the long axis of the antenna floor, and the long axis of the parasitic long microstrip is parallel to the long axis of the antenna floor. The tail end of the parasitic short microstrip is connected to the head end of the parasitic long microstrip, and the head end of the parasitic short microstrip is connected to the long side of the antenna floor.

The short-circuit strip is L-shaped, including short-circuit short strips and short-circuit long strips with long axes perpendicular to each other. The short-circuit short strip and the short-circuit long strip are on the same plane and are perpendicular to the plane where the antenna floor is located. The long axis is parallel to the long axis of the antenna floor, and the long axis of the short-circuit long strip is perpendicular to the long axis of the antenna floor. One end of the short-circuit short strip is connected to the middle of the excitation short microstrip, the other end is connected to one end of the short-circuit long strip, and the other end of the short-circuit long strip is connected to the end point of the long side of the antenna floor.

The antenna floor is a rectangular sheet, and its head is connected with the short-circuit strip and the parasitic microstrip. The tail of the antenna floor is folded toward the tail of the excitation microstrip to form a flanging, and the plane where the flanging is located is perpendicular to the plane where the antenna floor is located.

The sheet-shaped parasitic short microstrip, parasitic long microstrip, short-circuited short strip, short-circuited long strip and excitation short microstrip are on the same plane. In addition, the feed point of the antenna is located at the head end of the excitation short microstrip, the ground point of the antenna is located at the edge of the antenna floor corresponding to the head end of the excitation short microstrip, and the short-circuit point of the antenna is located at the connection position between the edge of the antenna floor and the short-circuit long strip .

The excitation microstrip, parasitic microstrip, short-circuit strip and antenna floor are an integral structure of metal sheets. The short-circuit strip, the excitation microstrip, the parasitic microstrip and the antenna floor in the utility model are cut into a predetermined shape by a thin metal sheet, and then folded.

The built-in antenna of the utility model adopts the design of combined use of additional parasitic unit and space back and forth technology, and applies the antenna structure to two frequency bands of TD-SCDMA terminal communication ingeniously. The utility model has the advantages of small size, low cost, simple structure, easy integration with other equipment, etc. while realizing the dual frequency band work required by the TD-SCDMA standard, and can effectively work in the 1880 frequency band used by TD-SCDMA. Two frequency bands of -1920MHz and 2010-2025MHz reflect the requirements of terminal antenna miniaturization, simple structure and dual-frequency operation in a relatively balanced manner.

Description of drawings

Fig. 1 is the three-dimensional structure schematic diagram of the present utility model;

FIG. 2 is a schematic plan view of the expanded structure of FIG. 1 .

Detailed ways

Embodiments of the utility model are described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the antenna mainly consists of four parts: excitation microstrip 1, parasitic microstrip 2, short circuit strip 3 and antenna floor 4. Among them, the excitation microstrip 1 is connected to the antenna floor 4 through the short-circuit strip 3, and is used as the main radiation unit of the antenna to generate the lower working frequency band of the antenna; the parasitic microstrip 2 is used as the secondary radiation unit of the antenna, and is coupled with the excitation microstrip 1 Feed, together as the radiation part of the antenna, its existence enables the antenna to resonate in a higher operating frequency band. The tail of the antenna floor 4 is folded toward the tail of the excitation microstrip 1 to form a flange 5 , and the plane where the flange 5 is located is perpendicular to the plane where the original antenna floor 4 is located. The three-dimensional structure is beneficial to the installation of the antenna, and at the same time can suppress the edge scattering phenomenon in the electromagnetic region of the antenna. The impedance characteristics of the antenna are improved by adjusting the shape and relative position of the excitation microstrip, the parasitic microstrip, and the distance from the feed point to the short-circuit point, and the dual-frequency broadband resonance of the antenna unit is realized.

The excitation microstrip 1 is L-shaped, including a strip-shaped excitation short microstrip and an excitation long microstrip whose major axes are perpendicular to each other. The plane where the excitation short microstrip is located is perpendicular to the plane where the excitation long microstrip is located, the plane where the excitation short microstrip is located is perpendicular to the plane where the antenna floor 4 is located, and the plane where the excitation long microstrip is located is parallel to the plane where the antenna floor 4 is located. The long axis of the excitation short microstrip is perpendicular to the long axis of the antenna floor 4 , and the long axis of the excitation long microstrip is parallel to the long axis of the antenna floor 4 . The tail end of the excitation short microstrip is connected with the head end of the excitation long microstrip.

The parasitic microstrip 2 is L-shaped, including long parasitic short microstrips and long parasitic strips whose major axes are perpendicular to each other. The parasitic short microstrip and the parasitic long microstrip are on the same plane and are perpendicular to the plane where the antenna floor 4 is located. The long axis of the parasitic short microstrip is perpendicular to the long axis of the antenna floor 4, and the long axis of the parasitic long microstrip is perpendicular to the antenna floor 4. long axis parallel. The tail end of the parasitic short microstrip is connected to the head end of the parasitic long microstrip, and the head end of the parasitic short microstrip is connected to the long side of the antenna floor 4 .

The short-circuit strip 3 is L-shaped, including short-circuit short-circuit strips and short-circuit long strips whose major axes are perpendicular to each other. The long axis of the strip is parallel to the long axis of the antenna floor 4 , and the long axis of the short-circuit long strip is perpendicular to the long axis of the antenna floor 4 . One end of the short-circuit short strip is connected to the middle of the excitation short micro-strip, the other end is connected to one end of the short-circuit long strip, and the other end of the short-circuit long strip is connected to the endpoint of the long side of the antenna floor 4.

The antenna floor 4 is a rectangular sheet, and its head is connected with the short-circuit strip and the parasitic microstrip. The tail of the antenna floor is folded toward the tail of the excitation microstrip to form a flange 5, and the plane where the flange 5 is located is perpendicular to the plane where the antenna floor is located.

The sheet-like parasitic short microstrip, parasitic long microstrip, short-circuit short strip, short-circuit long strip and excitation short microstrip are on the same plane; the excitation long microstrip and the antenna floor 4 are on two mutually parallel planes, and the two The planes parallel to each other are respectively perpendicular to the plane where the parasitic microstrip 2 is located.

The excitation microstrip 1, parasitic microstrip 2, short-circuit strip 3 and antenna floor 4 included in the antenna are unfolded into a plane as shown in FIG. 2 . The excitation microstrip 1, the short circuit strip 3 and the antenna floor 4 of the antenna are folded 90° inwardly along the folding lines ①, ②, and ③ shown by the dotted lines, so that the entire antenna unit forms a curved and repeatedly zigzag spatial structure. After three simple foldings along the folding line, the volume of the antenna unit is greatly reduced and the structure of the antenna unit is more compact. Points A, B, and C are the feed point, short-circuit point, and ground point of the antenna, respectively. There is a feeding protection interval between the feeding point A and the grounding point C, and the feeding point A and the grounding point C can be connected to the internal circuit of the mobile communication device through a coaxial cable. The positions of A, B, and C are determined according to the design requirements, and their positions determine the impedance bandwidth and operating frequency of the antenna; if the positions of the feed point A, short-circuit point B, and ground point C are moved, the impedance bandwidth and operating frequency will also change accordingly. The feed point A of the antenna is located at the head end of the excitation short microstrip, the short-circuit point B is located at the position where the edge of the antenna floor 4 is connected to the short-circuit long strip, and the ground point C is located at the head end of the excitation short microstrip corresponding to the edge of the antenna floor 4 .

The utility model reasonably arranges the size of each part of the antenna, the distance between the parts and the installation positions of the feed point A and the ground point C, so that the antenna has two discrete resonant frequencies: f1=1900MHz, f2= 2018MHz.

Claims (1)

1, a kind of built-in antenna comprises the little band of excitation of sheet, parasitic little band, short circuit band and antenna floor, it is characterized in that:

The little band of described excitation is L shaped, the short little band of excitation and the long little band of excitation that comprise the orthogonal sheet strip of long axis, the plane at the short little band of excitation place is vertical with the plane at the long little band of excitation place, the plane at the short little band of excitation place is vertical with the plane at place, antenna floor, the plane at the long little band of excitation place and the plane parallel at place, antenna floor; The long axis of the short little band of excitation is vertical with the long axis on antenna floor, and the long axis of the long little band of excitation is parallel with the long axis on antenna floor; The afterbody end of the short little band of excitation is connected with the head end of the long little band of excitation;

The little band of described parasitism is L shaped, the short little band of parasitism and the parasitic long little band that comprise the orthogonal sheet strip of long axis, parasitic short little band is in same plane and all vertical with the plane at place, antenna floor with parasitic long little band, the long axis of parasitic short little band is vertical with the long axis on antenna floor, and the long axis of parasitic long little band is parallel with the long axis on antenna floor; The afterbody end of parasitic short little band is connected with the head end of parasitic long little band, and the head end of parasitic short little band is connected with the long limit on antenna floor;

Described short circuit band is L shaped, the short band of short circuit and the long band of short circuit that comprise the orthogonal sheet strip of long axis, the short band of short circuit is in same plane and all vertical with the plane at place, antenna floor with the long band of short circuit, the long axis of the short band of short circuit is parallel with the long axis on antenna floor, and the long axis of the long band of short circuit is vertical with the long axis on antenna floor; One end of the short band of short circuit is connected with the middle part of the short little band of excitation, and the other end is connected with an end of the long band of short circuit, and the other end of the long band of short circuit is connected with the end points on long limit, antenna floor;

Described antenna floor is the sheet rectangle, and its head is connected with parasitic little band with the short circuit band, and the afterbody on antenna floor is folded to form flange to the caudal directions of the little band of excitation, and the plane at flange place is vertical with the plane at place, antenna floor;

The little band of described excitation, parasitic little band, short circuit band and antenna floor are the integrative-structure of sheet metal.

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