Richard M Dougherty

US Patent:

48765163, Oct 24, 1989

Filed:

Jan 27, 1989

Appl. No.:

7/302525

Inventors:

Richard M. Dougherty - Scottsdale AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H03F 360

US Classification:

330 54

Abstract:

A distributed amplifier which increases gain by increasing transconductance comprises a plurality of amplifying elements. Each element includes a darlington amplifier connected in cascade with a FET (field effect transistor) amplifier. The darlington amplifier includes an RC (resistance/capacitance) feedback loop from the drain to the gate. Each of the amplifying elements are coupled in parallel between an input transmission line and an output transmission line. The output transmission line operates as a recombining network as the input signals pass through the amplifying elements. To further increase gain and power output, a time delay line is coupled to each end of the output transmission line. The time delay line simulates the terminating elements normally associated with distributed amplifiers, and collects unguided signals from the output transmission line to recombine them with guided signals at the output. These unguided signals are terminated in conventional distributed amplifiers resulting in approximately a 3 dB (decibal) loss in gain.

US Patent:

48433543, Jun 27, 1989

Filed:

Nov 18, 1988

Appl. No.:

7/273647

Inventors:

Ronald D. Fuller - Mesa AZ
Richard M. Dougherty - Scottsdale AZ
Craig L. Fullerton - Scottsdale AZ
Hugh R. Malone - Phoenix AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01P 122
H01P 115

US Classification:

333 81A

Abstract:

Inductorless bias networks include a bias circuit having a bias return path which is coupled to and biases a variable impedance device in a relatively nonconductive state. Another bias circuit including a FET renders the variable impedance device relatively conductive in response to control signals so that one port is coupled to another port, for instance.

US Patent:

51948338, Mar 16, 1993

Filed:

Nov 15, 1991

Appl. No.:

7/792568

Inventors:

Richard M. Dougherty - Scottsdale AZ
Ronald F. Kielmeyer - Tempe AZ
Michael Dydyk - Scottsdale AZ
Lyle A. Fajen - Scottsdale AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01P 508

US Classification:

333 33

Abstract:

The performance of microwave coplanar and other circuit boards is improved by providing local matching elements for adjusting the characteristic impedance of local transmission line segments to better match the input or output impedance of the particular devices to which they couple. This is accomplished by providing a conductive bridge over the active lead of the transmission line, thereby lowering its characteristic impedance. This is very useful for narrow transmission line segments needed to make contact to small active device and/or MMIC's and which otherwise exhibit a substantial impedance mismatch with such small elements.

US Patent:

54654203, Nov 7, 1995

Filed:

Aug 18, 1994

Appl. No.:

8/292944

Inventors:

Richard M. Dougherty - Scottsdale AZ
Glenn R. Fraser - Scottsdale AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04B 128

US Classification:

455333

Abstract:

A non-linear active device (32), such as a FET, multiplies multiplicand signals to generate a product signal. A combining circuit (24) combines multiplicand signals into a combined signal. An input matching and conditioning network (28) couples the combined signal to an input of the active device (32). This network (28) matches impedances between sources for the multiplicand signals and the active device (32) at the frequencies of the multiplicand signals, and desirably shorts the product signal's frequencies. A feedback resistor (36) couples between the output and input of the active device (32) to lower impedance at the output and to stabilize the active device (32). An output matching and conditioning network (40) couples a mixed signal from the output of the active device to an output circuit (42). This network (40) matches impedances between the output circuit (42) and the active device (32) at the frequencies of the product signal, and desirably shorts the multiplicand signals' frequencies.

US Patent:

53875478, Feb 7, 1995

Filed:

Oct 23, 1992

Appl. No.:

7/965319

Inventors:

Richard M. Dougherty - Scottsdale AZ
Ronald F. Kielmeyer - Tempe AZ
Michael Dydyk - Scottsdale AZ
Lyle A. Fajen - Scottsdale AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01L 2158
H01L 2160

US Classification:

437182

Abstract:

A method for providing local matching elements for adjusting the characteristic impedance of local transmission line segments to more closely match the input or output impedance of the particular devices to which they couple. The method includes the step of providing a conductive bridge over the active lead of the transmission line, thereby lowering its characteristic impedance. The method can be applied to narrow transmission line segments needed to make contact to small active devices and/or MMIC's and which otherwise exhibit a substantial impedance mismatch with the small elements.

US Patent:

51442663, Sep 1, 1992

Filed:

Feb 4, 1991

Appl. No.:

7/650120

Inventors:

Richard M. Dougherty - Scottsdale AZ
Stephen W. Boser - Phoenix AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H03H 1138

US Classification:

333 1

Abstract:

A broadband high frequency active MMIC circulator which includes low parasitic devices (MESFETs or HEMTs) and shunt feedback for impedance contouring in conjunction with a cascode/cascade isolation/gain network. To achieve circulation, a common series feedback node is required for each active element. While conventional active circulator topologies require the use of a resistive element for operation with a deleterious effect on noise performance, this broadband high frequency active MMIC circulator functions with either resistive or reactive common series feedback. When reactive feedback is selected, major improvements in noise performance can be realized.

US Patent:

59865180, Nov 16, 1999

Filed:

Jun 30, 1998

Appl. No.:

9/109282

Inventors:

Richard Matthew Dougherty - Scottsdale AZ

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01P 512
H03F 368

US Classification:

333117

Abstract:

A distributed MMIC active quadrature hybrid (10) provides in-phase (I) and quadrature-phase (Q) outputs (22, 24) over an octave bandwidth. The quadrature hybrid includes in-phase and quadrature-phase amplifying elements (14, 12) arranged in a distributed manner. The in-phase amplifying elements (14) include FETs (42) with series inductive feedback (44) in the source path. The quadrature-phase amplifying elements (12) includes FETs (52) with series capacitive feedback (54) in the source path. The series inductive and capacitive feedback provides the phase difference between the hybrid's outputs. The FETs of the in-phase and quadrature-phase amplifying elements have differing gate peripheries to provide amplitude tracking over the bandwidth.