Tunable horn antenna

• US 6,867,744 B2
• Filed: 04/11/2002
• Issued: 03/15/2005
• Est. Priority Date: 04/11/2001
• Status: Expired due to Fees

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Wireless Corporation (Kyocera Corporation)
• Inventors: Toncich, Stanley, Tran, Allen
• Primary Examiner(s): Wimer, Michael C.
• Application Number:
  US10/122,399
• Publication Number:
  US 20020149533A1
• Time in Patent Office: 1,069 Days
• Field of Search: 343/772, 343/783, 343/785, 343/786
• US Class Current: 343/786
• CPC Class Codes: G01R 27/2694 Measuring dielectric loss, e.g. loss angle, loss factor or power factor
• CPC Class Codes: H01G 7/06 having a dielectric selected for the variation of its permittivity with applied voltage, i.e. ferroelectric capacitors electrets H01G7/02
• CPC Class Codes: H01L 27/0808 Varactor diodes
• CPC Class Codes: H01P 1/203 Strip line filters
• CPC Class Codes: H01P 1/20336 Comb or interdigital filters
• CPC Class Codes: H01P 1/20363 Linear resonators
• CPC Class Codes: H01P 1/20381 Special shape resonators
• CPC Class Codes: H01P 1/2039 Galvanic coupling between Input/Output
• CPC Class Codes: H01P 1/2056 Comb filters or interdigital filters with metallised resonator holes in a dielectric block
• CPC Class Codes: H01P 1/213 combining or separating two or more different frequencies H01P1/215 takes precedence
• CPC Class Codes: H01P 5/04 with variable factor of coupling
• CPC Class Codes: H03B 5/04 Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
• CPC Class Codes: H03B 5/124 the means comprising a voltage dependent capacitance
• CPC Class Codes: H03B 5/1262 the means comprising switched elements
• CPC Class Codes: H03B 5/1293 having means for achieving a desired tuning characteristic, e.g. linearising the frequency characteristic across the tuning voltage range
• CPC Class Codes: H03B 5/1841 the frequency-determining element being a strip line resonator H03B5/1805, H03B5/1817, H03B5/1864 and H03B5/1882 take precedence
• CPC Class Codes: H03B 5/362 the amplifier being a single transistor H03B5/364 - H03B5/368 take precedence
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/372 : Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 3/191 : Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H03H 7/0123 : comprising distributed impedance elements together with lumped impedance elements
• CPC Class Codes: H03H 7/12 : Bandpass or bandstop filters with adjustable bandwidth and fixed centre frequency H03H7/09 takes precedence; automatic control of bandwidth in amplifiers H03G5/16
• CPC Class Codes: H03H 7/20 : Two-port phase shifters providing an adjustable phase shift
• CPC Class Codes: H03J 5/246 : using electronic means H03J5/244 takes precedence
• CPC Class Codes: H03L 1/022 : by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature H03L1/021 takes precedence
• CPC Class Codes: H03L 7/18 : using a frequency divider or counter in the loop H03L7/20, H03L7/22 take precedence
• CPC Class Codes: H04B 1/0053 : with common antenna for more than one band
• CPC Class Codes: H04B 1/0458 : Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/30 : for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04B 1/40 : Circuits

Abstract

A family of FE dielectric-tuned antennas and a method for frequency tuning a wireless communications antenna are provided. The method comprises: forming a radiator; forming a dielectric with ferroelectric material proximate to the radiator; applying a voltage to the ferroelectric material; in response to applying the voltage, generating a dielectric constant; and, in response to the dielectric constant, communicating electromagnetic fields at a resonant frequency. Some aspects of the method further comprise: varying the applied voltage; and, modifying the resonant frequency in response to changes in the applied voltage. Modifying the resonant frequency includes forming an antenna with a variable operating frequency responsive to the applied voltage. Alternately stated, forming an antenna with a variable operating frequency includes forming an antenna with a predetermined fixed characteristic impedance, independent of the resonant frequency.

Claims

1. A horn antenna with a selectable operating frequency, the horn antenna comprising:

a radiator horn;

a dielectric with ferroelectric material proximate to the radiator, the dielectric having a varying dielectric constant responsive to a voltage applied to the ferroelectric material; and

,

wherein the horn has an electrical length responsive to the dielectric constant.

2. The horn antenna of claim 1 wherein the antenna has a predetermined fixed characteristic impedance independent of the resonant frequency.

3. The horn antenna of claim 1 wherein the antenna has a predetermined approximately constant gain independent of the resonant frequency.

4. The horn antenna of claim 1 wherein the electrical length of the horn is constant with respect to the resonant frequency.

5. The horn antenna of claim 1 wherein the dielectric includes:

at least one dielectric layer formed from a first material with a fixed dielectric constant; and

,

a dielectric formed from a ferroelectric material with a variable dielectric constant, adjacent the dielectric with the fixed dielectric constant.

6. The horn antenna of claim 5 wherein the dielectric formed from the ferroelectric material overlies the dielectric with the fixed dielectric constant.

7. The horn antenna of claim 5 wherein the dielectric formed with the fixed dielectric constant overlies the dielectric formed from the ferroelectric material.

8. The horn antenna of claim 5 wherein the dielectric with the fixed dielectric constant forms a first layer underlying the dielectric with the ferroelectric material, and a second layer overlying the dielectric with the ferroelectric material.

9. The horn antenna of claim 5 wherein the dielectric with the ferroelectric material is formed internal to the dielectric with the fixed dielectric constant.

10. The horn antenna of claim 5 wherein the dielectric with the ferroelectric material is formed external to the dielectric with the fixed dielectric constant.

11. The horn antenna of claim 1 wherein the dielectric with ferroelectric material is formed from barium strontium titanate, Ba_xSr_1-xTiO₃ (BSTO).

12. The horn antenna of claim 11 wherein the BSTO ferroelectric material includes oxide dopants selected from the group including tungsten, manganese, and magnesium.

13. The horn antenna of claim 11 wherein the dielectric with ferroelectric material has a dielectric constant that doubles in response to a change of less than 1 volt of bias voltage.

14. The horn antenna of claim 11 wherein the dielectric with ferroelectric material has a dielectric constant in the range between 100 and 5000 at zero volts.

15. The horn antenna of claim 5 wherein the dielectric formed from the first material with a fixed dielectric constant and the dielectric formed from the ferroelectric material have a composite dielectric constant in the range between 2 and 100 at zero volts.

16. The horn antenna of claim 1 wherein the dielectric with ferroelectric material is formed in a thin film layer having a thickness in the range from 0.15 to 2 microns.

17. The horn antenna of claim 1 wherein the dielectric material is formed in a thick film having a thickness in the range from 1.5 to 1000 microns.

18. The horn antenna of claim 1 further comprising:

a signal feed selected from the group including a coaxial cable, circular waveguide, rectangular waveguide, and a parallel plate signal feed.