Microwave double balanced mixer

Claim 2

A double balanced mixer comprising: first and second coplanar conductors forming a first slot transmission line, said first coplanar conductor being at a first D.C. potential and said second coplanar conductor being at a second different D.C. potential, a second slot transmission line intersecting said first slot transmission line, a first microstrip transmission line for coupling a first signal at a first frequency to a first portion of said second slot transmission line, a second microstrip transmission line for coupling a second signal at a second frequency to a second portion of said slot line, four nonlinear unidirectional current conducting devices connected at said intersection of said slot transmission lines to combine said first and second signals to provide along said first slot transmission line a third signal at a third frequency, and means for coupling said third signal from said first slot transmission line.

Claim 3

In combination, a first planar conductor at a first D.C. potential and a second coplanar conductor at a second different D.C. potential, said conductors forming with a dielectric substrate a continuous slot transmission line ring intersected by a second planar slot transmission line having a first section on one side of said intersection terminated in said second conductor and a second section on another side of said intersection terminated in said first conductor, said intersection providing first and second conductive corners in said first conductor and third and fourth conductive corners in said second conductor, means for coupling a first signal at one frequency and a second signal at a second frequency to said second slot transmission line, nonlinear unidirectional current conducting means interconnected between said corners to combine said first and second signals to propagate in said slot transmission line ring a third signal at a third frequency, and means for coupling said third signal from said slot transmission line ring.

Claim 4

In combination, a first planar conductor at a first D.C. potential and a second coplanar conductor at a second different D.C. potential, said conductors forming with a dielectric substrate a continuous slot transmission line ring intersected by a second planar slot transmission line having a first section on one side of said intersection terminated in said second conductor and a second section on another side of said intersection terminated in said first conductor, said intersection providing first and second conductive corners in said first conductor and third and fourth conductive corners in said second conductor, means for coupling a first signal at one frequency and a second signal at a second frequency to said second slot transmission line, nonlinear unidirectional current conducting means interconnected between said corners to combine said first and second signals to propagate in said slot transmission line ring a third signal at a third frequency, and means for coupling said third signal from said slot transmission line ring.

Claim 5

The combination as claimed in claim 2, said first and second planar conductors being on one side of said substrate, said first signal coupling means including a conductive strip on the opposite side of said substrate forming with said first planar conductor a first microstrip transmission line with said conductive strip passing across one section of said second slot transmission line to couple said first signal from said first microstrip transmission line to said second slot transmission line, said second signal coupling means including a second conductive strip on said opposite side of said substrate forming with said first planar conductor and said second coplanar conductor a second microstrip transmission line with said second conductive strip passing across the other section of said second slot transmission line to couple said second signal from said second microstrip transmission line to said second slot transmission line.

Claim 6

The combination as claimed in claim 3, said respective first and second conductive strips passing across said respective sections of said second slot transmission line at right angles.

Claim 7

The combination as claimed in claim 4, one of said conductive strips also passing across said slot transmission line ring at a low relatively impedance point along said ring.

Claim 8

The combination as claimed in claim 3, said third signal coupling means including a third microstrip transmission line circuit providing an efficient transmission path for said third signal and a low impedance path to ground for said first and second signals.

Claim 9

The combination as claimed in cLaim 6, said third signal coupling means including a band stop filter resonant at said first and second signal frequencies, said third microstrip transmission line coupled to said ring at a predetermined point along said ring from said intersection to provide a high impedance at said intersection at said first and second signal frequencies.

Claim 10

The combination as claimed in claim 7, said predetermined point being determined to provide first and second electrically equal length paths along said ring from said intersection, said paths having a length (2n + 1) lambda /4, where n is an integer and lambda is the slot line wavelength at an average of said first and second signal frequencies.

Claim 11

The combination as claimed in claim 6, said nonlinear unidirectional current conducting means including first, second, third and fourth diodes each having an anode and a cathode, the anode of said first diode being connected to said first corner and the cathode of said first diode being connected to said third corner diagonally opposite said first corner, the anode of said second diode being connected to said second corner and the cathode of said second diode being connected to said fourth corner, the anode of said third diode being connected to said fourth corner and the cathode of said third diode being connected to said first corner, the anode of said fourth diode being connected to said third corner and the cathode of said fourth diode being connected to said second corner.

Claim 12

A double balanced mixer having first, second, third and fourth nonlinear diodes, comprising: first and second coplanar conductive sheets forming a continuous slot transmission line ring intersected by a second coplanar slot transmission line having a first section terminated in said second conductive sheet and a second section terminated in said first conductive sheet, said intersection having first and second conductive corners in said first conductive sheet and third and fourth conductive corners in said second conductive sheet with the anode of said first diode connected to said first conductive corner and the cathode of said first diode connected to said third conductive corner diagonally opposite said first conductive corner, the anode of said second diode connected to said second conductive corner and the cathode of said second diode connected to said fourth conductive corner, the anode of said third diode connected to said fourth conductive corner and the cathode of said third diode connected to said first conductive corner, the anode of said fourth diode connected to said third conductive corner and the cathode of said fourth diode connected to said second conductive corner, means for coupling a first signal at frequency f1 to said second slot transmission line, said first planar conductive sheet having a first D.C. potential and said second planar conductive sheet having a second different D.C. potential, means for coupling a second signal at a frequency f2 to said second slot transmission line, whereby said signals are processed by said diodes to provide a third signal at frequency f3, and means for coupling said third signal at frequency f3 from said slot transmission line ring.

Claim 13

A double balanced mixer having first, second, third and fourth nonlinear diodes, comprising: first and second coplanar conductive sheets forming a continuous slot transmission line ring intersected by a second coplanar slot transmission line having a first section terminated in said second conductive sheet and a second section terminated in said first conductive sheet, said intersection having first and second conductive corners in said first conductive sheet and third and fourth conductive corners in said second conductive sheet with the anode of said first diode connected to said first conductive corner and the cathode of said first diode connected to said third conductive corner diagonally opposite said first conductive corner, the anode of said second diode connected to said second conductive corner and the cathode of said second diode connected to said fourth conductive corner, the anode of said third diode connected to said fourth conductive corner and the cathode of said third diode connected to said first conductive corner, the anode of said fourth diode connected to said third conductive corner and the cathode of said fourth diode connected to said second conductive corner, means for coupling a first signal at frequency f1 to said second slot transmission line, said first planar conductive sheet having a first D.C. potential and said second planar conductive sheet having a second different D.C. potential, means for coupling a second signal at a frequency f2 to said second slot transmission line, whereby said signals are processed by said diodes to provide a third signal at frequency f3, and means for coupling said third signal at frequency f3 from said slot transmission line ring.