JPS6032401A - Band pass filter - Google Patents

Abstract

PURPOSE:To obtain a stable characteristic and also to attain miniaturization and light weight of a microwave communication device by providing a prescribed hole to a dielectric substrate between half-wavelength resonators or the half- wavelength resonator and an input/output line. CONSTITUTION:The dielectric substrate 3 is provided with the resonators 1 made of conductor thin film and the input/output lines 2. The amount of coupling among the resonators 1 depends on the interval of the resonators and the size and number of the holes. Since the dielectric constant is decreased substantially by providing the holes, the size of the dielectric substrate 3 is decreased by providing the holes above and the interval between the half-wavelength resonators or the half-wavelength resonator and the input/output line is narrowed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bandpass filter that is used in a microwave band communication device and is composed of a microwave integrated circuit (+viIC).

In recent years, as microwave band communication equipment has become smaller and lighter, F-band F wave devices, which used to be composed of waveguides or coaxial lines, have become smaller and lighter.
Microwave integrated circuits (iviICs) in which a resonator is constructed of a thin film conductor on a dielectric substrate have come to be manufactured. These +VI I C band offshore transducers are extremely difficult to design, especially when the bandwidth is narrow, and as a result, the product has the drawback of poor performance stability.

First, a bandpass p-wave filter (hereinafter referred to as BPF) will be explained. FIG. 1 is a plan view showing an example of the configuration of a conventional MIC BPF. A plurality of half-wavelength resonators 1 and input/output lines 2 formed of thin film conductors are spaced apart from each other by a distance d. 1. d engineering 2.・
... are arranged in parallel to each other so that they are coupled with the required amount of electromagnetic coupling.

In this type of BPF, when the fractional bandwidth (parameter obtained by dividing the passband width by the center frequency) is 10% to 15%, almost the designed electrical performance can be obtained. However, when the fractional bandwidth becomes several inches, a very small amount of electromagnetic coupling is required between each resonator and between the input/output line and the resonator, and the distance d is required. □
It becomes necessary to increase r d1□, .

The amount of electromagnetic coupling is determined by the electromagnetic field distribution between the resonator conductors. This is illustrated in the cross-sectional view of Figure 1! ! This will be explained using Figure 2. That is, the resonator 1 on the substrate 3 and the substrate 3
An inter-frequency electric field E is generated between the conductor 4 and the ground conductor 4 on the lower side, and a high-frequency magnetic field H exists orthogonal thereto. The coupling between these resonators 1 is caused by the intersection of high-frequency magnetic fields H, and when the resonator spacing dlj is smaller than 1.5 times the resonator conductor width W, the amount of coupling between the resonators 1 is analyzed from the electromagnetic field distribution. It is in good agreement with the amount of binding. However, the resonator spacing d
As ij increases to twice or triple the resonator conductor width W, the actual amount of coupling becomes even greater than the amount of coupling determined by electromagnetic field analysis.

The causes of this are: 1) There is an effect of electromagnetic field leakage, which is not treated in normal electromagnetic field analysis, and 2) The dielectric substrate acts as a type of dielectric waveguide, and electromagnetic waves propagate within this dielectric. 3) As the resonator spacing increases, the dielectric substrate inevitably becomes thicker, thus accommodating the dielectric substrate.

It is conceivable that the case (usually a metal conductor) becomes thicker, making it easier for the waveguide mode (space propagation mode) to propagate and couple to the resonator conductor.

It is extremely difficult to analyze the electromagnetic field of these elements, and it is nearly impossible to quantitatively grasp the amount of coupling. Also, the shape of the case that houses the dielectric substrate.

It is difficult to evaluate the performance of a single dielectric substrate because it is affected by its dimensions. Therefore, the conventional narrowband IVi
The design dimensions of most IC-based BPFs are determined through repeated trial production and experimentation, and performance varies due to dimensional errors in manufactured products, making it extremely difficult to obtain stable performance.

An object of the present invention is to provide a narrow-band IVC-based BPF'f which eliminates the drawbacks of the conventional technology and has stable performance.

The configuration of the present invention is a bandpass filter consisting of a microwave integrated circuit including half-wavelength resonators and input/output lines formed on one surface of a dielectric substrate by a thin film conductor and electromagnetically coupled to each other. By providing a predetermined hole in the dielectric substrate between each half-wavelength resonator or between these half-wavelength resonators and the input/output line, It is characterized by narrowing the interval between.

The present invention will be explained in detail below with reference to the drawings.

FIG. 3 is a plan view of an embodiment of the invention. In the figure,
1 is a resonator made of a conductive thin film, 2 is a human output line, 3 is a dielectric substrate, and 5 is a hole provided in the dielectric substrate, which is a feature of the present invention. In this case, the amount of coupling between the resonators 1 is determined by the resonator spacing and the size and number of holes. By providing such a hole, the dielectric constant can be substantially reduced, so the spacing between these resonators 10 can be reduced.

Therefore, the dielectric substrate 3 can be made smaller, and the generation of waveguide 2-' mode due to the case can be prevented.
Since electromagnetic wave propagation within the dielectric is blocked by the hole 5,
Electromagnetic coupling between resonators due to this effect can also be ignored. That is, the MIC BPF of the present invention can reduce the effects of two of the three uncertain factors that caused the defects of conventional products to a negligible extent.

Therefore, the number of repetitions of trial production and experiments for determining design dimensions is reduced, and variations in electrical performance between products are also small, resulting in stable characteristics. Furthermore, since the dielectric substrate can be made smaller, it is highly effective in reducing the size and weight of microwave communication devices.

Although the bandpass P-wave device has been described in detail above, the present invention can also be expected to be effective in the case of an LVi I C band-stop p-wave device (hereinafter referred to as BgF). FIG. 4 shows a plan view of an embodiment of *vi I C-ized BEF according to the present invention. By providing the hole 5 between the input/output line 2 and the resonator 1, the distance can be reduced to do1' and uncertain coupling can be prevented. Further, by providing the holes 5 between the resonators 1, inter-resonator coupling harmful to the BEF can be reduced, as in the case of the BPF.

In the above explanation, the circular hole 5 VC was explained, but it goes without saying that the same effect can be obtained by using an oval or gigantic hole instead of the circular hole.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional MIC bandpass filter;
The figure is a longitudinal cross-sectional view showing the coupling between the resonators in FIG. FIG. 2 is a plan view showing a second embodiment. In the figure, 1... Half wavelength resonator, 2... Input/output line, 3... Dielectric substrate, 4...
Ground conductor, 5... hole made in the dielectric substrate. ' ~ Agent Patent Attorney Uchihara 1' Day, □,. ′−−−′ Joy/Figure

Claims (1)

[Claims] In a bandpass filter consisting of a microwave integrated circuit having a plurality of half-wavelength resonators formed of a thin film conductor on one surface of a dielectric substrate and provided with a plurality of half-wavelength resonators electromagnetically coupled to each other and a human output line, each half-wavelength resonance By providing a predetermined hole in the dielectric substrate between the half-wavelength resonators or between the half-wavelength resonators and the input/output line, the interval between the half-wavelength resonators or between the half-wavelength resonators and the input/output line can be narrowed. Bandwidth wave device that is % similar to what you did.