Inverted-F ferroelectric antenna

• US 6,937,195 B2
• Filed: 02/09/2004
• Issued: 08/30/2005
• Est. Priority Date: 04/11/2001
• Status: Expired due to Fees

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Wireless Corporation (Kyocera Corporation)
• Inventors: Fabrega-Sanchez, Jorge, Toncich, Stanley S., Tran, Allen
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US10/775,722
• Publication Number:
  US 20040222925A1
• Time in Patent Office: 568 Days
• Field of Search: 343/700.MS, 343/702, 343/787, 343/829, 343/846, 343/909
• US Class Current: 343/700.0MS
• 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: H01Q 1/00 Details of, or arrangements associated with, antennas arrangements for varying orientation of directional pattern H01Q3/00
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 13/02 Waveguide horns
• CPC Class Codes: H01Q 13/06 Waveguide mouths horns H01Q13/02
• CPC Class Codes: H01Q 13/203 Leaky coaxial lines
• CPC Class Codes: H01Q 3/44 varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: H01Q 9/0442 with particular tuning means
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence
• 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 2200/372 Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 3/191 Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H03H 7/20 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 1/30 : for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

An inverted-F ferroelectric antenna is provided. The antenna comprises a counterpoise, or groundplane, and a radiator structure having a first end and a second end. A capacitor, formed from a ferroelectric dielectric is interposed between the second end of the radiator and the counterpoise. The capacitor has a variable dielectric constant, and the antenna is resonant at a frequency responsive to the dielectric constant of the capacitor ferroelectric material. Typically, the capacitor includes a dielectric formed from a fixed constant dielectric, together with a ferroelectric dielectric with a variable dielectric constant. A bias voltage feed is used to apply a voltage to the capacitor ferroelectric dielectric. The ferroelectric dielectric has a dielectric constant that varies in response to the applied voltage.

Claims

1. A patch antenna comprising:

a counterpoise;

a radiator having a first end and a second end;

a first dielectric interposed between the second end of the radiator and the counterpoise; and

a first capacitor formed from a dielectric with ferroelectric material, having a variable dielectric constant, interposed between the radiator second end and the counterpoise, wherein the antenna is resonant at a frequency responsive to the dielectric constant of the first capacitor ferroelectric material.

2. The antenna of claim 1 further comprising a radio frequency (RF) antenna interface for connecting the radiator to a transmission line first polarity and connecting the counterpoise to the transmission line second polarity, the interface having a predetermined fixed characteristic impedance independent of the resonant frequency.

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

4. The antenna of claim 1 wherein the first capacitor includes:

a dielectric formed from a material with a fixed dielectric constant; and

a dielectric formed from a ferroelectric material with a variable dielectric constant, wherein the antenna has a resonant frequency responsive to the variable dielectric constant of the ferroelectric material.

5. The antenna of claim 1 further comprising a bias voltage feed for applying a voltage to the first capacitor, wherein the first capacitor ferroelectric dielectric has a dielectric constant that varies in response to the applied voltage.

6. The antenna of claim 5 wherein the first capacitor has a first terminal connected to the bias voltage feed and a second terminal connected to the counterpoise;

and, wherein the bias voltage feed applies a first voltage potential across the first capacitor.

7. The antenna of claim 6 wherein the first capacitor includes:

at least one fixed constant dielectric layer; and

a ferroelectric dielectric with a variable dielectric constant, adjacent the fixed constant dielectric.

8. The antenna of claim 6 further comprising a bias voltage blocking capacitor interposed between the second end of the radiator and the first terminal of the first capacitor, the second end of the radiator being connected to the counterpoise.

9. The antenna of claim 8 wherein the blocking capacitor is formed from a dielectric with ferroelectric material.

10. The antenna of claim 8 further comprising a third capacitor formed from a dielectric with ferroelectric material, having a variable dielectric constant, interposed between a transmission line first polarity and the radiator;

and, wherein the characteristic impedance of the transmission line is responsive to the dielectric constant of the third capacitor ferroelectric material.

11. The antenna of claim 6 further comprising a bias voltage blocking capacitor interposed between the first end of the radiator and the counterpoise.

12. The antenna of claim 11 wherein the blocking capacitor is formed from a dielectric with ferroelectric material.

13. The antenna of claim 11 wherein the bias voltage feed is supplied to a transmission line first polarity connected to the radiator.

14. The antenna of claim 11 further comprising a third capacitor formed from a dielectric with ferroelectric material, having a variable dielectric constant, interposed between a transmission line first polarity and the radiator;

and, wherein the characteristic impedance of the transmission line is responsive to the dielectric constant of the third capacitor ferroelectric material.

15. The antenna of claim 5 wherein the first capacitor is a gap capacitor having the first and second terminals formed as pads, separated by a gap, overlying a layer of ferroelectric dielectric.

16. The antenna of claim 13 wherein the first capacitor includes the layer of ferroelectric dielectric overlying a layer of fixed constant dielectric.

17. The antenna of claim 5 wherein the first capacitor is a parallel plate capacitor having the first terminal formed as a plate, overlying a layer of ferroelectric dielectric, overlying a layer of fixed constant dielectric, overlying the second terminal formed as a plate.

18. The antenna of claim 1 wherein the combination of the first capacitor and the radiator have an effective electrical wavelength of a quarter-wavelength of the resonant frequency.

19. The antenna of claim 1 wherein the first capacitor includes a dielectric formed exclusively from a ferroelectric material with a variable dielectric constant;

and, wherein the antenna has a resonant frequency responsive to the variable dielectric constant of the ferroelectric material.