2D transmission line-based apparatus and method

• US 20070030102A1
• Filed: 04/28/2006
• Published: 02/08/2007
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Bhat, Harish, Afshari, Ehsan, Hajimiri, Seyed
• Granted Patent: US 7,456,704 B2
• Time in Patent Office: Days
• US Class Current: 333/263
• CPC Class Codes: H01P 5/12 Coupling devices having more than two ports H01P5/04 takes precedence

Abstract

A power combiner comprising an LC lattice structure is shown, together with a method for generating a planar wave front. The LC structure can comprise constant or voltage dependent capacitors. Either the delay or the characteristic impedance of the two-dimensional transmission line formed by the LC lattice structure are kept constant. A planar wave propagating along one direction of the transmission line gradually experiences higher impedances at the edges, creating a lower resistance path for the current in the middle. This funnels more power to the center as the wave propagates.

Claims

1. A power combiner comprising:

a first plurality of segments serially distributed along a first direction;

a second plurality of segments serially distributed along a second direction; and

a plurality of nodes formed by intersection of the first plurality of segments with the second plurality of segments, each node associated with a series inductance of the first plurality of segments, a series inductance of the second plurality of segments and a capacitance,

wherein the first and second plurality of segments form a transmission line having a propagration velocity and a characteristic impedance, and

wherein one between the propagtion velocity and the characteristic impedance is constant and the other between the propagation velocity and the characteristic impedance is variable.

2. The power combiner of claim 1, wherein the propagation velocity is kept constant along the first direction and the characteristic impedance is increased along the second direction.

3. The power combiner of claim 1, wherein at least one among series inductance and capacitance is variable in space.

4. The power combiner of claim 1, wherein series inductance and capacitance are constant in space.

5. The power combiner of claim 2, wherein at least one between the series inductance of the first plurality of segments, series inductance of the second plurality of segments and capacitance has a nonlinear current-dependent or voltage-dependent behavior.

6. The power combiner of claim 1, wherein a ground plane is associated to the segments along the first direction, the power combiner comprising different metal layers as said ground place at different points along said first direction.

7. The power combiner of claim 6, wherein the different metal layers are four different metal layers.

8. The power combiner of claim 1, wherein a variable depth ground place is associated to the segments along the first direction.

9. A method for generating a planar wave front, comprising:

providing two-dimensional transmission line comprising inductors and capacitors, said transmission line having a delay and a characteristic impedance;

keeping constant one between the delay and the characteristic impedance and varying the other between the delay and the characteristic impedance; and

inputting a plurality of signal sources to the transmission line.

10. The method of claim 9, comprising:

keeping the delay constant along a first dimension of the transmission line; and

increasing the characteristic impedance along the second dimension of the transmission line, whereby the planar wave front propagates along the first dimension.

11. The method of claim 9, wherein values of the inductors and capacitors are variable along a first dimension or the second dimension.

12. The method of claim 9, wherein values of the inductors and capacitors are constant along a first dimension or the second dimension.