Multilayered band separator with grounding parasitic capacitor

• US 6,677,833 B2
• Filed: 04/17/2002
• Issued: 01/13/2004
• Est. Priority Date: 09/21/2001
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Sheen, Jyh-Wen
• Primary Examiner(s): Cunningham, Terry D.
• Assistant Examiner(s): TRA, ANH QUAN
• Application Number:
  US10/123,234
• Publication Number:
  US 20030058063A1
• Time in Patent Office: 636 Days
• Field of Search: 333/132, 333/126, 333/128, 333/129, 333/134, 333/176, 333/185
• US Class Current: 333/132
• CPC Class Codes: H03H 7/46 Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source for use in multiplex transmission systems H04J1/00

Abstract

A multilayer band separator with a grounding parasitic capacitor. The separator includes a quasi-highpass filter, a semi-lumped lowpass filter and a phase shifter. The quasi-highpass filter includes a third capacitor connected to an input signal, a fourth capacitor with one end connected to the third capacitor and the other end connected to ground, an inductive element with one end connected to ground and the other end connected to the connection point of the third and fourth capacitors, and a second capacitor with one end connected to the connection point of the third capacitor, the fourth capacitor and the inductive element and the other end connected to a second output to pass a high-frequency output signal. The phase shifter is a transmission line element connected to the input signal. The semi-lumped lowpass filter includes an inductive element with one end connected to the end of the phase shifter without the input signal and the other end connected to a first output to pass a low-frequency output signal, and a first capacitor connected in parallel to the inductive element.

Claims

1. A multilayered band separator with grounding parasitic capacitor, capable of separating a high-frequency signal and a low-frequency signal from an operating band with an input signal input by an input port, comprising:

a quasi-highpass filter, having three capacitive devices and a grounding inductive device in a cross-shaped implementation to be the high-frequency signal output passage, wherein a capacitive device is a grounding pararistic capacitor formed by the two other capacitive devices;

a phase shifter, connected in parallel to the quasi-highpass filter, to provide the low-frequency signal output passage; and

a semi-lumped lowpass filter, connected in series to the phase shifter, to produce a higher outband rejection without an additional filter stage.

2. The multilayered band separator of claim 1, wherein the cross-shaped implementation is a third capacitor connected to the input port, a fourth capacitor with an end connected to the third capacitor and another end connected to grounding, an inductive device with an end connected to grounding and another end connected to the connection point of the third and fourth capacitors, and a second capacitor with an end connected to a second output end and another end connected to the connection point of the third and fourth capacitors and the inductive device to pass a high-frequency output signal.

3. The multilayered band separator of claim 1, wherein the phase shifter is a transmission line device connected to the input signal.

4. The multilayered band separator of claim 1, wherein the semi-lumped lowpass filter comprises an inductive device with an end connected to a first output end and another end connected to another end of the phase shifter to pass a low-frequency output signal, and a first capacitor connected across the inductive device.

5. The multilayered band separator of claim 1, wherein the operating band for the low-frequency signal ranges between 800-1000 MHz.

6. The multilayered band separator of claim 1, wherein the operating band for the high-frequency signal ranges between 1700-2000 MHz.