Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:
A description is given, with reference to the accompanying drawings, of embodiments of the present invention.
The ring filter device 10A includes a substrate 11A made of dielectric, and has a different configuration to that of the ring filter device 10 shown in
An open stub part 14A of the ring filter device 10A is designed to have a high impedance Z3 of, e.g. 100Ω, so as to narrow the frequency band A.
The substrate 11A is made of a dielectric epoxy resin (relative dielectric constant (εr0)). The open stub part 14A is formed on a dielectric fluororesin part 20, which is made of a different material from that of the substrate 11A. A relative dielectric constant (εr1) of fluororesin is lower than the relative dielectric constant (εr0) of epoxy resin, thereby satisfying εr1<εr0.
However, in the first embodiment, the relative dielectric constants satisfy εr1<εr0; therefore, a width W2 of the open stub part 14A can be increased by several mm as shown in
When the substrate 11A is manufactured by injection molding, coinjection molding is employed. As shown in
The substrate 11A can also be manufactured by the same steps performed for manufacturing a printed wiring board, by laminating plural pre-impregnated layers (hereinafter referred to as “prepreg”). Specifically, as shown in
The ring filter device 10B includes a substrate 11B made of dielectric, and has a different configuration to that of the ring filter device 10 shown in
An open stub part 14B of the ring filter device 10B is designed to have a low impedance Z3 of, e.g. 10Ω, so as to widen the frequency band A.
The substrate 11B is made of a dielectric epoxy resin (relative dielectric constant (εr0)). The open stub part 14B is formed on a dielectric PPO part 50, which is made of a different material from that of the substrate 11B. A relative dielectric constant (εr2) of PPO is higher than the relative dielectric constant (εr0) of epoxy resin, thereby satisfying εr2>εr0. PPO is an abbreviation of polyphenylene oxide.
However, in the second embodiment, the relative dielectric constants satisfy εr2>εr0; therefore, a width W4 of the open stub part 14B can be decreased by several mm as shown in
The ring filter device 10C includes a substrate 11C made of dielectric, and has a different configuration to that of the ring filter device 10 shown in
The substrate 11C is formed by laminating special prepreg sheets, and a glass cloth is only included in a peripheral part thereof. Accordingly, the substrate 11C includes a part without glass cloth 60. The part without glass cloth 60 is square-shaped. The peripheral part corresponds to a part with glass cloth, which is denoted by 61. Each of the prepreg sheets is formed by impregnating a glass cloth with epoxy resin.
As shown in
The ring part 13 and the open stub part 14 are formed on the part without glass cloth 60.
The glass cloth causes instabilities in the dielectric constant and dielectric loss of the substrate 11C, increases the dielectric loss of the substrate 11C, and forms convexities and concavities on the surface of the substrate 11C.
The part without glass cloth 60 only includes epoxy resin, and is therefore unaffected by the glass cloth, so that the dielectric constant is stable, the dielectric loss is low, and the flatness of the surface is good.
The dielectric constant is stable and the dielectric loss is low in the part without glass cloth 60, and therefore, the ring filter device 10C has a desired transmission property near design value.
Further, the surface of the part without glass cloth 60 has good flatness, and therefore, the ring part 13 and the open stub part 14 made of copper foil have good flatness. Thus, a current loss along the surface of the ring part 13 and the open stub part 14 is reduced compared to a case where the flatness is not good. Accordingly, the ring filter device 10C has a desired transmission property near design value.
The ring filter device can be made with a composite epoxy substrate instead of the dielectric substrate 11C. The surface of the composite epoxy substrate has good flatness, so that current loss along the surface is reduced. Therefore, the ring filter device can have a desired transmission property near design value.
In the ring filter device 10D, a ring filter element 12D having an open stub is arranged on a top surface of a substrate 11D. The ground pattern 15 entirely covers the bottom surface of the substrate 11D. The ring filter element 12D having the open stub includes a ring part 13D and an open stub part 14D. The open stub part 14D protrudes into the ring part 13D. The open stub part 14D is formed on a fluororesin part 20D of the substrate 11D.
In the ring filter device 10D, the width of the open stub part 14D can be made to have an appropriate dimension. Further, the ring filter device 10D can be made compact than other examples where the open stub part protrudes out from the ring part.
The ring filter element 83 having an open stub includes a ring part 84 and an open stub part 85.
The UWB flat panel antenna device 80 includes a fluororesin part 90. The open stub part 85 is formed on the fluororesin part 90, and has an appropriate width that is easy to manufacture, so that the freedom in the design of the UWB flat panel antenna device 80 is higher than conventional products.
The UWB flat panel antenna device 100 includes a ring filter device 10E mounted on the top surface of a flat panel antenna body 110.
As shown in
The ring filter device 10E is substantially the same as the ring filter device 10A shown in
The ring filter device 10E is mounted onto the position between the line 113 and the line 114, with the line 16 connected to the line 113 and the line 17 connected to the line 114.
A substrate 121 is formed by laminating special prepreg sheets, and a glass cloth is only included in a periphery part 122 thereof. Accordingly, the substrate 121 includes a part without glass cloth 123.
On the top surface of the substrate 121, microstrip lines 131, 132, 133, 134 are formed in parallel, partly overlapping one another. A ground pattern 125 entirely covers the bottom surface of the substrate 121.
The coupling constants between the microstrip line 131 and the microstrip line 132, the microstrip line 132 and the microstrip line 133, and the microstrip line 133 and the microstrip line 134 are controlled by distances and overlapping amounts therebetween, thereby achieving a desired frequency property.
The microstrip lines 131, 132, 133, 134 are formed on the part without glass cloth 123.
The part without glass cloth 123 has a stable dielectric constant and a low rate of dielectric loss. Therefore, the edge coupled filter device 120 has a desired transmission property near design value.
Further, the surface of the part without glass cloth 123 has good flatness, and therefore, surfaces of the microstrip lines 131, 132, 133, 134 made of copper foil have good flatness. Thus, a current loss along the surface of the microstrip lines 131, 132, 133, 134 is reduced compared to a case where the flatness is not good. Accordingly, the edge coupled filter device 120 has a desired transmission property near design value.
The present invention is not limited to the specifically disclosed embodiment, and variations and modifications may be made without departing from the scope of the present invention.
The present application is based on Japanese Priority Patent Application No. 2006-131700, filed on May 10, 2006, the entire contents of which are hereby incorporated by reference.
Number | Date | Country | Kind |
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2006-131700 | May 2006 | JP | national |