Patent Application
20130099978
1. Field of the Invention
The present invention relates to an internal printed antenna, especially to an internal printed antenna used for LTE700, GSM850/900, PCS, DCS, UMTS, LTE2300, and LTE2500 system operation without increasing antenna size.
2. Description of Related Art
Along with fast development of communication technology and popularity of electronic products, a plurality of communication protocols and technologies of wireless signal transmission have been developed. Wireless communication is more widely used by people and many portable electronics such as mobile phones and PDA can send receive signals in different bands for more powerful communication capacities.
Generally, portable electronics are built-in with a dual-band or tri-band antenna so as to send and receive signals in different bands. However, such antenna operates only in two or three separate bands, without ranging bands commonly used. Refer to U.S. Pat. No. 6,727,854, a planar inverted-F antenna is revealed. The operating frequency band of the antenna is within bands of the GSM900 system and the DCS system.
Moreover, refer to Taiwanese Patent Pub. App. No. 1254493, a dual-band inverted-F antenna is disclosed. By two radiating elements having a T-shaped radiating metal part and an adjustment metal sheet, bandwidth, impedance matching and gain of the antenna are adjusted to achieve dual-frequency or multiple frequency operation. However, the frequency of bands available now is lower. Such design not only increases the antenna size that occupies space and doesn't meet requirements of light weight and compact design. Moreover, the multi-pathway resonance makes the antenna structure become more complicated. The manufacturing processes are complex and the cost is increased.
Therefore it is a primary object of the present invention to provide an internal printed antenna whose frequency band ranges most of commonly used wireless communication systems including LTE700, GSM850/900, PCS, DCS, UMTS, LTE2300, LTE2500, etc without increasing antenna size so as to overcome above shortcomings.
In order to achieve the above object, an internal printed antenna of the present invention includes a dielectric substrate, a ground plane, a metal loop radiating portion, and a microstrip feed line. The dielectric substrate consists of a first surface and a second surface corresponding to the first surface and the ground plane is disposed on the first surface for signal ground. Then the metal loop radiating portion is formed on the first surface by printing or etching and is connected to an edge at one side of the ground surface. The metal loop radiating portion is composed of a plurality of bends and a gap area is formed between adjacent bends. The gap area is arranged with two short circuit parts. Then the microstrip feed line is corresponding to the metal loop radiating portion and is disposed on the second surface. One end of the microstrip feed line is a signal feeding end of the antenna while the other end thereof is a coupling end. The coupling end consists of a rectangular main body and two extending parts connected to the rectangular main body. The rectangular main body includes a vertical first slot having an opening at one end, a horizontal slot connected to the first slot, and a vertical second slot having one end connected to the horizontal slot. Moreover, the extending parts are respectively located at the left side and right side of the rectangular main body 5. The extending parts include a rectangular first extending part connected to the right side of the rectangular main body and an L-shaped second extending part connected to the left side of the rectangular main body. The first extending part and the second extending part are extending from the right side and the left side of the rectangular main body symmetrically.
Thereby double pathway resonance is generated by the two short circuit parts at the gap area. This results in resonance at different frequencies to reach a wide-band. Next impedance matching of the antenna is adjusted by the microstrip feed line without increasing the antenna volume and is used for LTE700, GSM850/900 PCS, DCS, UMTS, LTE2300, and LTE2500 system operation.
The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein:
Refer from
The dielectric substrate 1 includes a first surface 11 and a second surface 12 corresponding to the first surface 11. In this embodiment, the dielectric substrate 1 is made from FR4 epoxy fiberglass.
The ground plane 2 is arranged on the first surface 11 for signal ground.
The metal loop radiating portion 3 is located at the first surface 11 and is connected to an edge at one side of the ground surface 2. The metal loop radiating portion 3 includes a plurality of bends 31 while a gap area 32 formed between adjacent bends 31. The gap area 32 is disposed with at least one short circuit part 33. In this embodiment, there are two short circuit parts 33.
The microstrip feed line 4 is corresponding to the metal loop radiating portion 3 and is arranged at the second surface 12. Refer to
Furthermore, the thickness, the length and the width of the dielectric substrate 1 in this embodiment are respectively 0.8 mm, 110 mm, and 50 mm. The metal loop radiating portion 3 is formed on the first surface 11 by printing or etching and is able to generate full wavelength at 820 MHz. The impedance of the microstrip feed line is 50 ohm. The dielectric substrate 1 is further disposed with a connector 7 that passes through the ground plane 2 and the dielectric substrate 1. The connector 7 is connected to the signal feeding end 41 of the microstrip feed line for feeding signals. The connector 7 can be a 50 ohm SMA (SubMiniature version A) connector.
Refer to
Refer from
In summary, firstly use the metal loop radiating portion to produce full wavelength at 820 MHz. Then generate multiple resonance through double pathways by the two short circuit parts 33 of the gap area 32. The resonance at different frequencies causes a wide-band. Moreover, the impedance matching of the whole antenna is adjusted by the microstrip feed line 4 without increasing the volume of the whole antenna. Thus the start frequency and stop frequency of the low frequency band are 690 MHz and 970 MHz while the start frequency and stop frequency of the high frequency band are 1700 MHz and 3000 MHz.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalent.
