Charles F Clark - RF Engineering

over 30 years of RF Engineering


I have de­signed VCO’s, frequency synthesizers, low noise amplifiers and power amplifiers. I am experienced in matching complex loads over wide frequency ranges. The technologies have included multilayer PCB designs and thick and thin film hybrids. I have designed filters with passbands up to 70 GHz and stopbands to 110 GHz.

I am currently using Microwave Office and Axiem the EM solver for circuit analysis. I have been using Eagle from Cadsoft for PCB layout. I own my licenses for each. I have also used ADS and HFSS.

As an innovative project leader, I effectively allocate tasks and motivate team members to put forth their best efforts. I possess excellent communication skills, which enable me to ensure that my team members understand their tasks and their roles. I work within cost, personnel and time con­straints to achieve profitable results. I enjoy working on reliability and design yield problems.

Bluestem Consulting, Inc, Prosper, Texas     March 2015 - present    

Contract with various companies, providing RF Design, modeling and testing activities related to the designs. 

RDRTec Dallas, Texas

Contract System Modeling Engineer      June 2013 to 2015

◦   Modeled AESA receiver system using VSS

Tektronix, Inc. Beaverton, Oregon

Senior Microwave Engineer                   January 2011 to 2014

◦   Designed and built filters using Genesys and HFSS up to 70 GHz. These were filter incorporated into filter banks on thin film or into multilayer co-fired ceramics for IC packages.

Used VSS to model system for wideband receiver.

ACI Technologies Philadelphia, Pa

Contract Engineer                                  July 2010 to October 2010

◦   Analyzed and solved receiver front end problem on a new SDR. Goal was to fix design issues within 2 months. This was completed with 1 week to spare including test time. Problems addressed were the AGC system and receiver spurious. The design changes included, the LNA, RF and IF filters and AGC system. The design included RF amplifiers and UHF filters as well as IF filters.

◦    I also worked on the bid for the Low Cost Open Architecture Radar.

◦   ACI was working on system and subsystem verification.

South West Research Institute,  San Antonio, Texas

Contract Engineer                                  March 2010 to June 2010

◦   Designed a 10 GHz frequency synthesizer for a communications project. The synthesizer selected was capable of both integer N and Fractional N division.

◦   Laid out board with Eagle and did circuit analysis with Microwave Office. The design included an active tripler and an interdigital filter.

◦   The microstrip filter was simulated with Axiem.

Meshlinx Wireless Inc. Richardson, Texas

Director of Hardware Engineering         September 2006- January 2009

◦   Designed power amplifiers for 2.4 and 5.8 GHz WiFi system with LNA’s and switching power supplies. PA’s worked on OFDM.

◦   Responsible for receiving FCC and IC type acceptance for a wireless access point.

◦   Managed the development of antennas for the backhaul link.

Synergy Microwave Inc. Paterson, New Jersey

Design Engineer                                    November 2005 to September 2006

◦   Designed low noise, wideband VCO’s in the 100 MHz to 6 GHz range.

◦   Resolved production problems related to component tolerances.

◦   Fixed manufacturing problems to increase yield.

Conexant Systems Inc. Irving, Texas

Applications Engineer                            November 2000 to May 2002

◦   Assisted cell phone manufacturers getting their dual band GSM phones into production using Conexant chipset.

◦   Resolved EMC problems and circuit board layout problems.

◦   Tried to anticipate problems and correct them before they would delay production.

◦   Wrote a software manual for the control system of the cell phone DSP.

◦   Wrote an application note on the selection of the crystal for the reference oscillator.

Vari-L Denver, Colorado

Product Line Manager,                           November 1998 to September 2000

◦   Led a Hybrid Oscillator design group with products aimed at military and space markets. Products range in frequency from 25 MHz to 7 GHz.

◦   Leading the group into distributed elements and statistical design resulting in higher frequency operation and higher profits through higher yields. Started using ADS to model oscillators.

◦   Held a secret clearance.

Texas Instruments, Inc. Dallas, Texas

RF Systems Engineer,                           August 1995 to November 1998

◦   Held responsibility for the design, development, and implementation of new systems.

◦   Worked exten­sively on the concep­tual design and creation of integrated RF power amplifiers. In addi­tion, generated new product specifications and frequency plans

◦   Designed a new RF transceiver for a CDMA/AMPS, dual band cellular phone, including a frequency plan receiver, transmitter, and synthesizer.

◦   ·Developed a new, compact mon­o­lithic capacitor, and subsequently awarded a patent. US #6,177,716,B1

◦   Pioneered a new transceiver architecture, which greatly increased battery life, which was a key customer re­quirement.

Advanced Energy Fort Collins, Colorado

Staff Engineer, RF Products,                  August 1992 to July 1995

◦   Served as the technical contact for the company's largest RF customer.

◦   Made changes to the de­sign approach, which reduced the amount variation in a product, in response to an in­crease in product sales from $3,000,000 to $40,000,000 annually.

◦   RF amplifiers were Class E high efficiency amplifiers.

◦   Developed several new products based on existing products to reduce time to market. These developments included a pulsing plasma source, a plasma source for highly elec­tron-absorbent plasma sources, and an entirely new plasma source for the sterilization of medical tools.

◦   Led the effort to develop a new plasma source for tungsten silicide etching.

Northrop Electronics Rolling Meadows, Illinois

Senior Engineering Specialist,               July 1984 to July 1992

◦   Worked as the senior engineer in an advanced receiver development group, a power am­plifier team designing GaAs integrated circuits, and a product design group.

◦   Designed broadband ECCM receiver subsystems.

◦   Designed a 6-18 GHz GaAs power amplifier

◦   Cor­rect­ed an SC cut crystal oscillator manufacturing problem, and improved the phase noise of a VHF VCO module.

◦   Equipment was for airborne military applications.

◦   Held a secret clearance with special access.

◦   Fixed synthesizer noise problem.


1984     Master of Science Program Engineering Technology

            M.S. Degree: Thesis Topic-800 MHz Land Mobile Receiver

            Northern Illinois University, DeKalb, Illinois

1972     B.S. Microbiology, University of Illinois, Champaign, Illinois


◦   VHF Power Amplifiers

◦   Measuring Phase Noise

◦   Lightning Protection

◦   Power Supply for Power Fets

◦   Tips for Low Noise VCO's

Professional Affiliations

◦   Senior Member of IEEE

◦   Exhibits Co-Chairman of the 1992 Joint Symposia of the APS of the IEEE, URSI, and NEM

◦   Past Chairman of Joint Chicago Chapter of the AP-S and MTT-S of the IEEE

◦   Past Vice Chairman and Secretary/Treasurer Joint Chicago Chapter of the AP and MTT Soci­eties of the IEEE


◦   Officer, North Texas Microwave Society,

◦  Past- President, Central States VHF Society,

◦   Life Member Amateur Radio Relay League


◦   Low Loss Capacitor, US # 6,177,716 B1. This improved capacitor construction resulting in a higher capacitor Q for monolithic power amplifiers.

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