Electrically tunable notch filters

• US 20060152303A1
• Filed: 03/06/2006
• Published: 07/13/2006
• Est. Priority Date: 12/12/2000
• Status: Abandoned Application

• Current Assignee: Khosro Shamsaifar, Xiao-Peng Liang
• Original Assignee: Khosro Shamsaifar, Xiao-Peng Liang
• Inventors: Shamsaifar, Khosro, Liang, Xiao-Peng
• Application Number:
  US11/369,109
• Publication Number:
  US 20060152303A1
• Time in Patent Office: Days
• US Class Current: 333/134
• CPC Class Codes: H01P 1/2039 Galvanic coupling between Input/Output
• CPC Class Codes: H01P 1/209 comprising one or more branching arms or cavities wholly outside the main waveguide
• CPC Class Codes: H01P 1/213 combining or separating two or more different frequencies H01P1/215 takes precedence

Abstract

An embodiment of the present invention provides n apparatus, comprising a wireless telephone handset comprising an antenna connection; a diplexer coupled to the antenna connection; a transmit section connected to a first port of the diplexer; a receive section connected to a second port of the diplexer; and wherein the diplexer includes first and second notch filters, each of the notch filters comprising a main transmission line, a first coupling mechanism, and a first electrically tunable resonator coupled to the main transmission line through the first coupling mechanism, wherein the first electrically tunable resonator includes a voltage tunable dielectric varactor and wherein a control unit provides control signals for controlling the voltage tunable dielectric varactor, thereby tuning the first and second notch filters to provide isolation between the transmit and receive frequencies.

Claims

1. An apparatus, comprising:

a wireless telephone handset comprising;

an antenna connection;

a diplexer coupled to the antenna connection;

a transmit section connected to a first port of the diplexer;

a receive section connected to a second port of the diplexer; and

wherein the diplexer includes first and second notch filters, each of the notch filters comprising a main transmission line, a first coupling mechanism, and a first electrically tunable resonator coupled to the main transmission line through the first coupling mechanism, wherein the first electrically tunable resonator includes a voltage tunable dielectric varactor and wherein a control unit provides control signals for controlling said voltage tunable dielectric varactor, thereby tuning said first and second notch filters to provide isolation between the transmit and receive frequencies.

2. The apparatus of claim 9, wherein said composite or doped voltage tunable dielectric material are selected from the group consisting of:

BSTO-MgO, BSTO-MgAl2O4, BSTO-CaTiO3, BSTO-MgTiO3, BSTO-MgSrZrTiO6, and combinations thereof.

3. The apparatus of claim 10, wherein said composite or doped voltage tunable dielectric material is a BSTO-composite ceramic material.

4. The apparatus of claim 9, wherein the first coupling mechanism comprises one of:

a first capacitive probe, a first inductive loop, a first iris window, a first evanescent waveguide piece, a first slot, and a first hole.

5. The apparatus of claim 9, wherein the main transmission line comprises one of:

a coaxial transmission line, a microstrip line, a stripline line, a rectangular waveguide, a coplanar waveguide, and a ridged waveguide.

6. The apparatus of claim 9, wherein each of the first and second notch filters further includes:

a second coupling mechanism; and

a second electrically tunable resonator coupled to the main transmission line through the second coupling mechanism, wherein the first and second coupling mechanisms are spaced ¼

wavelength apart at an operating frequency of the filter.

7. An apparatus, comprising:

a wireless telephone handset comprising;

an antenna connection;

a diplexer coupled to the antenna connection;

a transmit section connected to a first port of the diplexer;

a receive section connected to a second port of the diplexer; and

wherein the diplexer includes first and second notch filters, each of the notch filters comprise a bandpass filter connected between a termination and one of a circulator or a 3 dB hybrid, wherein the bandpass filter includes a voltage tunable dielectric varactor.