KR100258037B1 - Star type microwave super narrow band bpf using dielectric resonators mounted on angled coaxial cable - Google Patents

Abstract

PURPOSE: A star type ultrahigh frequency and narrow band pass filter having a dielectric resonance mounted to an angular coaxial line is provided to minimize a volume of a circuit and improve a narrow band feature. CONSTITUTION: An external conductor(60) of a square dielectric resonance is electrically connected to an external conductor of an angular coaxial line. A lead wire(50) is electrically connected to a center conductor(10) of the angular coaxial line. The angular coaxial line is electrically connected to the external conductor(60) of a square dielectric resonance through a dielectric material(30) of a microstrip line. An unit block is mounted at each surface of the angular coaxial line. A plurality of dielectric resonances are located at a plane perpendicular to an advance direction thereof. A block of multiple states is formed along an advance direction of a signal.

Description

Star Type Microwave Bandpass Filter with Dielectric Resonator on Square Coaxial Line

The present invention relates to a bandpass filter that can be applied to a communication and electrical energy transmission circuit in a frequency band of 500 MHz or more by installing a dielectric resonance resonator in a TEM mode on a square coaxial line.

At present, there is a rapid increase in the use of microwave systems for high value-added wireless services such as personal mobile phones, pagers, and WLLs. Therefore, the exponential demand for bandpass filters, a key component required for most communication devices, is expected to increase.

It is not possible to use the Lumped Circuit Element, which is used at low frequency, for the bandpass filter used in the above applications that use the frequency above 500 MHz and below about 5 GHz. (Distributed Circuit Element) should be used. In this case, there are problems such as not only the size of the component but also the insertion loss in the pass band, the attenuation in the stop band is low, and the difficulty in obtaining the transmission characteristics of the narrow band.

In order to solve this problem, a band pass filter is usually manufactured by using a dielectric resonator. An existing band pass filter (application number: 1995 patent application No. 53021) of the structure applied by the present inventors has a microstrip center when a dielectric resonator is mounted. It is cumbersome in manufacturing that dielectric film should be used because electrical separation from conductor is required. In case of another band pass filter (Application No. 53022, 1996), it is maximum in the plane perpendicular to the direction of travel. The disadvantage of not being able to attach more than two resonators does not achieve the desired narrowband characteristics. The present invention has a structural advantage of attaching a plurality of dielectric resonators in a limited space than in the conventional case, and in terms of characteristics, it is possible to obtain characteristics of low loss and narrow band, which are advantages of the two previously filed structures.

Accordingly, an object of the present invention is to manufacture a ultra narrow band pass filter having a new structure in which the volume of the circuit is miniaturized and the narrow band characteristics and insertion loss characteristics are improved in the pass band to solve the above problems.

In order to achieve the above object, the present invention is characterized by using only a square coaxial line, a square dielectric resonator of λ / 4 TEM (Transverse Electromagnetic) mode, and a distribution constant circuit such as a thin conductive line.

1 is a diagram showing a bandpass filter in which eight TEM mode dielectric resonators according to the present invention are mounted on an outer conductor of a square coaxial line (in the case of an octagonal coaxial line) using an inductive post.

FIG. 2 is a front view of the bandpass filter shown in FIG.

3 is a side view of the bandpass filter shown in FIG.

4 is a plan view of the bandpass filter shown in FIG.

FIG. 5 shows a dielectric resonator used in the bandpass filter shown in FIG.

* Explanation of symbols for main parts of the drawings

10: center line of square coaxial line 50: thin inductive post

20: outer conductor of square coaxial line 60: outer conductor of dielectric resonator (silver plating)

30 dielectric of square coaxial line 70 dielectric of dielectric resonator

40: square dielectric resonator in TEM mode

80: A metal stripped part of the outer conductor of a square coaxial line for connecting a dielectric resonator

Hereinafter, the configuration of the present invention will be described with reference to the accompanying drawings.

1 is a three-dimensional view of a bandpass filter using two stages using a square coaxial line (octagonal coaxial line) and eight TEM mode dielectric resonators according to the present invention. The number of resonators can be adjusted according to the desired band. By constructing such a structure in multiple stages at intervals of [lambda] / 4, the characteristics of the ultra narrow band can be obtained. 2 and 3, the outer conductor 20 of the square coaxial line is stripped to the bottom of the square dielectric resonator as shown in FIG. Electrically connect with (20). Along with this, the thin wire 50 electrically connected to the center conductor 10 of the square coaxial line is lowered down through the dielectric 30 of the microstrip line and electrically connected to the outer conductor 60 of the square dielectric resonator. The electrical connection is made without a gap so that the field does not leak. The unit blocks may be mounted on each side of the square coaxial line to place a plurality of dielectric resonators in a plane perpendicular to the traveling direction. Furthermore, by forming a plurality of blocks along the traveling direction of the signal, a plurality of blocks may be formed in a limited space, compared to the conventional case. Many resonators can be mounted.

The dielectric resonator of FIG. 5 used in the bandpass filter as described above uses a ceramic dielectric material 70 having high dielectric constant and low loss, and has a small size, low loss, and excellent attenuation characteristics.

As described above, the present invention uses a square coaxial line, a square dielectric resonator of λ / 4 TEM (Transverse Electromagnetic) mode, and a distribution constant circuit of a thin conductive line (Inductive Post). Ultra narrow bandpass filter characteristics can be obtained.

Claims (1)

Stripping the metal to the outer conductor 20 of the square coaxial line as the bottom size of the square dielectric resonator 40 (80), and the outer conductor 20 of the edge of the stripped portion and the outer conductor 60 of the square dielectric resonator And the thin wire 50 electrically connected to the center of the microstripline center conductor 10 is lowered through the dielectric 30 of the square coaxial line to the conductor 60 located at the center of the square dielectric resonator. It is a single block that consists of several resonators in accordance with the desired passband. Configuring these blocks in multiple stages for the desired band.