Zeroeth-order resonator

• US 7,391,288 B1
• Filed: 04/18/2007
• Issued: 06/24/2008
• Est. Priority Date: 03/26/2004
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Itoh, Tatsuo, Sanada, Atsushi, Caloz, Christophe
• Primary Examiner(s): Pascal; Robert J.
• Assistant Examiner(s): Glenn; Kimberly E
• Application Number:
  US11/737,088
• Time in Patent Office: 433 Days
• Field of Search: 333/219, 333/236, 333/239, 333/246
• US Class Current: 333/219
• CPC Class Codes: H01P 7/082 Microstripline resonators H01P7/088 takes precedence

Abstract

A high frequency resonator circuit and method of fabrication is described which has a resonant frequency independent of physical resonator dimensions. The resonator operates in a zeroeth-order mode on a composite right/left-handed (CRLH) transmission line (TL). The LH wave properties of the CRLH-TL contributing anti-parallel phase and group velocities. In one variation, the unit cells are formed from microstrip techniques, preferably creating alternating interdigitated capacitors and stub inductors. The resonant wavelength of the resonator is dependent on the electrical characteristics of the unit cells and not the physical size of the resonator in relation to the desired resonant wavelength. The resonator is created with at least 1.5 unit cells and the Q of the resonator is substantially independent of the number of unit cells utilized. The resonator circuit is particularly well suited for reducing resonator size, and allows resonators of various wavelengths to be fabricated within a fixed board area.

Claims

1. A resonator apparatus, comprising:

a resonator formed from a composite high frequency right/left-handed transmission line;

said resonator having an input port for coupling a high frequency signal into said resonator;

said resonator having an output port for coupling a high frequency signal out of said resonator;

wherein said transmission line is configured to resonate at the zeroeth-order characterized by an infinite-wavelength wave in the transmission line;

wherein said transmission line has a resonant frequency which is independent of the physical size characteristics of the resonator;

wherein said transmission line is formed from unit cells having a desired equivalent shunt inductance, shunt capacitance, series inductance, and series capacitance, within said transmission line; and

wherein left-handed aspects of said composite high frequency right/left-handed (CRLH) transmission line have an equivalent series capacitance and shunt inductance, while right-handed aspects of said composite high frequency right/left-handed (CRLH) transmission line have an equivalent series inductance and shunt capacitance.

3. A resonator apparatus as recited in claim 1 or 2:

wherein said resonator has a dispersion curve; and

wherein the slope of the dispersion curve is a function of the equivalent series inductance and shunt capacitance of the unit cells.

4. A resonator apparatus as recited in claim 3:

wherein an increasing slope corresponds to higher bandwidth at resonance and occurs when either said series inductance or shunt capacitance decreases; and

wherein a decreasing slope occurs when either said series inductance or shunt capacitance increases and corresponds to lower bandwidth at resonance.

5. A resonator apparatus as recited in claim 1 or 2:

wherein said resonator is defined in one dimension; and

wherein said resonator produces a single zeroeth order resonant frequency.

6. A resonator apparatus as recited in claim 1 or 2:

wherein said resonator comprises a multi-dimensional structure;

wherein said resonator produces a plurality of zeroeth order resonant frequencies; and

wherein the zeroeth order resonant frequency is defined by equivalent series and shunt capacitance and inductance.

2. A resonator apparatus, comprising:

a resonator formed from a composite high frequency right/left-handed transmission line;

wherein said transmission line is configured for providing anti-parallel phase and group velocities in response to the left-handed aspect of the composite high frequency right/left-handed transmission line;

wherein said transmission line includes at least 1.5 of said unit cells having inductors and capacitors formed as microstrips providing a desired equivalent shunt inductance and shunt capacitance within said transmission line;

at least one input and output port on said resonator for coupling high frequency signals into and out of said resonator;

wherein said transmission line is configured for resonating at the zeroeth-order characterized by an infinite-wavelength wave in the transmission line and has a resonant frequency which is independent of the physical size characteristics of the resonator; and

wherein left-handed aspects of said composite high frequency right/left-handed transmission line have an equivalent series capacitance and shunt inductance, while right-handed aspects of said composite high frequency right/left-handed transmission line have an equivalent series inductance and shunt capacitance.

7. A method of implementing high frequency resonators, comprising:

forming a composite right/left-handed (CRLH) unit cell configured to include left-hand wave operation for contributing anti-parallel phase and group velocities;

coupling at least 1.5 of said unit cells into a composite right/left-handed (CRLH) transmission line (TL) configured for resonating at the zeroeth-order characterized by an infinite-wavelength wave in the transmission line with a resonant frequency which is independent of the physical size characteristics of the resonator; and

coupling at least one input port and output port to said CRLH-TL;

wherein left-handed aspects of said composite high frequency right/left-handed (CRLH) transmission line have an equivalent series capacitance and shunt inductance, while right-handed aspects of said composite high frequency right/left-handed (CRLH) transmission line have an equivalent series inductance and shunt capacitance.

8. A method as recited in claim 7:

wherein said resonator has a dispersion curve; and

wherein the slope of the dispersion curve is a function of series inductance and shunt capacitance of the unit cells.

9. A method as recited in claim 8:

wherein an increasing slope corresponds to higher bandwidth at resonance and occurs when either series inductance or shunt capacitance decreases; and

wherein a decreasing slope occurs when either series inductance or shunt capacitance increases and corresponds to lower bandwidth at resonance.

10. A method as recited in claim 7:

wherein said resonator is defined in one dimension; and

wherein said resonator produces a single zeroeth order resonant frequency.

11. A method as recited in claim 7:

wherein said resonator comprises a multi-dimensional structure;

wherein said resonator produces a plurality of zeroeth order resonant frequencies; and

wherein the zeroeth order resonant frequency is defined by equivalent capacitance.