Photonic bandgap reflector-suppressor

• US 7,332,697 B2
• Filed: 12/23/2005
• Issued: 02/19/2008
• Est. Priority Date: 12/23/2005
• Status: Expired due to Fees

• Current Assignee: National Research Council Canada
• Original Assignee: National Research Council Canada
• Inventors: Vatsya, S. Raj
• Primary Examiner(s): ROBINSON, DANIEL LEON
• Application Number:
  US11/315,007
• Publication Number:
  US 20070145046A1
• Time in Patent Office: 788 Days
• Field of Search: 219/745, 219/746, 219/747, 219/748, 219/749, 219/756, 219/750, 219/728
• US Class Current: 219/745
• CPC Class Codes: H05B 6/74 Mode transformers or mode stirrers

Abstract

A computer-based design methodology for photonic bandgap devices that permits determination of both the upper and lower bandgap edges in either a one-dimensional or two-dimensional photonic crystal. Using this methodology, a one-dimensional crystal may be created for use in a waveguide-fed microwave oven as a radiation reflector-suppressor, particularly for undesirable higher harmonic frequencies of about 12 GHz. By conceptually arranging multiple reflectors in a desired geometry, a two-dimensional crystal may be created that is particularly useful as a waveguide or splitter. The waveguide or splitter thus created has especially high efficiency for microwave wavelength ranges of about 9 GHz as compared with the prior art and is particularly useful in communications applications.

Claims

1. A waveguide comprising a photonic bandgap crystal for use in directing or splitting incident photonic radiation, the waveguide comprising:

a) a block of a first material having a first dielectric constant, the block having a length, a width and a thickness;

b) a guide path for directing or splitting photonic radiation through the crystal, the guide path having a starting point on the width and at least one ending point on the length or width;

c) a plurality of cylindrical holes, each having a longitudinal axis parallel to the thickness and a radius perpendicular thereto, the holes provided along the length and width of the block outside the guide path and arranged in a triangular lattice having a lattice constant, the holes containing a second material having a second dielectric constant less than the first dielectric constant;

d) wherein the first dielectric constant is from 7.4 to 25, the second dielectric constant is from 0.9 to 1.1 and the ratio of the radius to the lattice constant is from 0.45 to 0.495.

2. The waveguide of claim 1, wherein the waveguide has an efficiency of at least 70%.

3. The waveguide of claim 1, wherein the first dielectric constant is about 12, the second dielectric constant is about 1 and the ratio of the radius to the lattice constant is 0.475.

4. The waveguide of claim 3, wherein the guide path is straight, bent, Y-shaped or pitchfork shaped, the frequency of the photonic radiation is from 9 to 13 GHz and wherein the waveguide has an efficiency of at least 44%.

5. The waveguide of claim 3, wherein the guide path is straight, the frequency of the photonic radiation is 9.3 GHz and wherein the waveguide has an efficiency of at least 85%.

6. The waveguide according to claim 1, wherein the photonic bandgap crystal has a periodic crystal structure and the guide path is bounded by an arrangement of a plurality of reflectors preserving the periodicity of the crystal structure.

7. The waveguide according to claim 2, wherein the photonic bandgap crystal has a periodic crystal structure and the guide path is bounded by an arrangement of a plurality of reflectors preserving the periodicity of the crystal structure.

8. The waveguide according to claim 3, wherein the photonic bandgap crystal has a periodic crystal structure and the guide path is bounded by an arrangement of a plurality of reflectors preserving the periodicity of the crystal structure.

9. The waveguide according to claim 4, wherein the photonic bandgap crystal has a periodic crystal structure and the guide path is bounded by an arrangement of a plurality of reflectors preserving the periodicity of the crystal structure.

10. The waveguide according to claim 5, wherein the photonic bandgap crystal has a periodic crystal structure and the guide path is bounded by an arrangement of a plurality of reflectors preserving the periodicity of the crystal structure.

11. The waveguide according to claim 1, further comprising at least one one-dimensional photonic bandgap crystal in the guide path.

12. The waveguide according to claim 4, further comprising at least one one-dimensional photonic bandgap crystal in the guide path.

13. The waveguide according to claim 6, further comprising at least one one-dimensional photonic bandgap crystal in the guide path.

14. The waveguide according to claim 9, further comprising at least one one-dimensional photonic bandgap crystal in the guide path.