Dielectric wave filter, communication apparatus and method for controlling resonant frequency

Abstract

The invention provides a dielectric filter including a metal case having an opening in the upper part, a metal lid of closing the opening, a dielectric resonance element placed on the internal bottom face of the case through a support, a bolt made of dielectric material inserted in a position in the lid corresponding to the dielectric resonance element, and a metal plate placed at the end of the bolt substantially in parallel with the upper face of the dielectric resonance element, wherein the position of the bolt is adjusted to change the space between the dielectric resonance element and the plate, whereby the resonance frequency is controlled.

Description

technical field [0001] The present invention relates to a dielectric filter, and more particularly, to a dielectric filter for use in mobile communication base stations such as cellular phones, broadcast radio wave transmission stations, and similar communication transmission stations, and using the dielectric filter device communication device. Background technique [0002] In recent years, cellular telephone systems have required highly sensitive transmission / reception characteristics and satisfactory call quality. The filter of the base station needs to have low-loss conduction characteristics with almost no attenuation of signal components, and characteristics of sharp attenuation that can reliably remove unwanted interference radio wave components. Filters meeting these needs include dielectric filters using dielectric resonators with high Q values. (see, for example, James. K. Plourde, "Dielectric Resonator Applications in Microwave Devices", "Institute of Electrical...

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Problems solved by technology

[0010] from Figure 17 It can be clearly seen in the figure that the dielectric filter 1000 has a disadvantage: that is, as the tuning device 1012 is inserted into it (that is to say, the insertion depth of the bolt 1006 increases), when the metal plate 1007 is close to the dielectric resonant element 1104, especially, the spurious resonant frequency Close to or at the same resonant frequency as the TE01 resonant mode, making it impossible to obtain the desired filtering characteristics

[0011] Likewise, the conventional dielectric filter 1000 also has the disadvantage that spurs cannot be completely shielded from the electromagnetic field coupling between adjacent dielectric resonant elements, which have the Coupling window 1010 formed by space

[0012] In addition, there is a disadvantage that when the coupling adjustment screw 1009 is inserted into the coupling window 1010, the influence of spurs in the electromagnetic field coupling between dielectric resonant elements becomes significant.

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