A kind of filter that contains rectangle resonance pole
Technical field
The present invention relates to the pectinate line cavity body filter, particularly a kind of filter that contains rectangle resonance pole.
Background technology
Fast development along with mobile communications industry; Mobile phone and personal digital assistant device have obtained application more and more widely, and towards high-performance, high power capacity; High-quality direction develops; The radio frequency that present communication system is adopted has covered very wide frequency band, and in order to improve the large-capacity communication quality, broadband filter has been adopted in the mobile communication base station.The mobile communication transmittability is based on the basis of bandwidth; The wideer higher throughput of bandwidth support; With satisfying the more requirement of high-capacity speed transmission of user, reduced the expense of management information simultaneously, have higher spectrum efficiency than the communication mode of expanding carrier wave.The operation principle of broadband filter is identical with other filters, is used in communication system the signal frequency in the communication link being selected, and difference is that the fixed percentage bandwidth of broadband filter is bigger, and message capacity is bigger.
Fixed percentage bandwidth (Fractional Bandwidth) is defined as: filter bandwidht/filter center frequency.
The fixed percentage bandwidth that the pectinate line cavity body filter of the cylindrical resonance post of present employing can be accomplished is about 15%; Sometimes can't satisfy the communication requirement of repeater or base station system; The technological means of taking through this patent; Can make the fixed percentage bandwidth of pectinate line cavity body filter reach 20%-25%, thereby improve message capacity greatly, save hardware resource.
Summary of the invention
The object of the invention is exactly a kind of stable performance is provided in order to overcome the defective that above-mentioned prior art exists, contains the filter of rectangle resonance pole reliably.
The object of the invention can be realized through following technical scheme: a kind of filter that contains rectangle resonance pole; It is characterized in that; Comprise cover plate, cavity, resonance post, flange, frequency tuning screw, the tuning threaded body that is coupled, described cover plate is located on the cavity, and described resonance post is located at the cavity inner bottom part; Described flange is located on the resonance post, and described frequency tuning screw, the tuning threaded body of coupling all are located on the cover plate.
Described cover plate and cavity are fixed through hold-down screw.
Described resonance post comprises two, and the bottom interconnects.
Described frequency tuning screw comprises two.
The tuning threaded body of described coupling comprises coupling tuning screw, suspension member, and this suspension member is fixed on coupling tuning screw bottom.
The tuning threaded body of described coupling is located in the middle of two frequency tuning screws.
Described frequency tuning screw is corresponding with resonance post inner chamber position.
Compared with prior art, the present invention has improved the fixed percentage bandwidth that filter can reach greatly; The signal transmission capacity and the efficient of communication systems such as base station, repeater have been improved; Stable performance, reliable; Simple in structure, be suitable for producing in batches.
Description of drawings
Fig. 1 is a kind of structure of cover plate sketch map that contains the filter of rectangle resonance pole of the present invention;
Fig. 2 is the structural representation of the cavity of a kind of filter that contains rectangle resonance pole of the present invention;
Fig. 3 is a kind of Filter Structures sketch map that contains rectangle resonance pole of the present invention.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment the present invention is described further.
Like Fig. 1, Fig. 2, shown in Figure 3; A kind of filter that contains rectangle resonance pole of the present invention comprises a cover plate 1 and a cavity 2, fixes with hold-down screw between cover plate and the cavity, and the cavity the inside scrapes out the groove shape; And at groove the inside installation resonance post 3; Be equipped with flange 4 above the resonance post, the resonance post is the cuboid form, and frequency tuning screw 5 and the tuning threaded body 6 of coupling are housed on the cover plate.Because the resonance column bottom is directly to connect together,, realize that filter has very wide fixed percentage bandwidth so can produce very strong coupling; And can change the size of the coupling between the resonance post through the height of change coupling part; It is high more to connect convex, and it is big more to be coupled, otherwise then more little; In addition, can effectively change the size of two couplings between the resonator through regulating two threaded bodies between the resonator, threaded body extend into that the cavity part is many more, and column part is thick more, and it is strong more to be coupled, otherwise then more little.Through above measure, can make the fixed percentage bandwidth of filter reach 20%-25%, realize the broadband coupled structure of pectinate line cavity body filter.
The electrical performance indexes of a band pass filter is that centre frequency is 905 MHz, and 3 dB bandwidth are 792-1018MHz, and the center Insertion Loss is less than 1.4dB, and return loss is less than-15dB.
This wave filter technology index fixed percentage bandwidth is (1018-792)/905=25%; So should adopt the filter construction of broadband of the present invention coupling; Through the requirement that can touch the mark of its bandwidth of debugging, therefore proved the feasibility of the filter construction of broadband coupling proposed by the invention.