CUSTOMER BACKGROUND

Some of the most interesting work in the microwave industry lies well outside

standard commercial wireless and military domains, and the products developed

by Meridian Medical Systems (MMS) for medical applications are compelling

examples. The company, founded in 1985 by industry luminary Dr. Kenneth

Carr, has applied the inherent characteristics of electromagnetic energy to

solve problems that have eluded other technologies. The result is a string

of awards for innovation from government and industry. MMS products use

microwave energy to generate heat, measure radiation and motion, and monitor

and maintain the temperature of blood and other fl uids. Carr, an Institute of

Electrical and Electronics Engineers (IEEE) Life Fellow, is considered a pioneer in

the medical application of microwave technology, and has nearly 40 patents in

the discipline. He founded ferrite products manufacturer Ferrotec, which was

acquired by M/A-COM. Dr. Carr made signifi cant contributions at M/A-COM,

retiring in 1990 as a group vice president and technical director. Since then he

has applied his talents exclusively to microwave medical technology at MMS.

THE DESIGN CHALLENGE

Cardiac arrhythmia (when the heart beats too slowly, too fast, or irregularly)

is typically treated with a procedure called cardiac ablation, which selectively

destroys tissue to ensure that the “signal” controlling the heartbeat follows

the proper path. A catheter is inserted into the patient’s leg that runs upward

and into the heart, where, through cryogenic cooling or electromagnetic or

ultrasonic radiation, the target tissue is destroyed. None of these techniques,

however, are able to provide real-time feedback about how much energy to

apply while the doctor is performing the procedure. The temperature sensor in

conventional catheters can measure only the value in the tip, which is typically

cooled, so the value returned is not very precise. Without an accurate feedback

mechanism, doctors tend to apply less-then-optimum energy levels to ensure the

safety of the patient, which can reduce the procedure’s effectiveness.

Meridian Medical Systems Applies Microwave Offi ce® To Improve the Treatment of a Critical Heart Condition

AWR®

SuccessStory

“I’ve found Microwave

Offi ce to be unique

among EDA tools

for its ability to make

the design process

comparatively simple.

Measurements

we’ve made on the

devices we received

from TriQuint agree

extremely well with

the Microwave Offi ce

simulation. In short,

we got back exactly

what we hoped for.”

Bob Allison Vice president/engineering manager

Meridian Medical Systemswww.mms-llc.com

Application:Cardiology

AWR Software:Microwave Offi ce®

AWR’s Software and TriQuint’s Foundry Process Make Company’s Radiometer Development a Painless Procedure

THE SOLUTION

To solve this problem, MMS is developing a catheter that combines the

ability to simultaneously deliver microwave radiation for tissue heating and a

radiometer (essentially a remote sensing device) fabricated as a microwave

monolithic integrated circuit (MMIC) to sense the temperature of the

heart wall. The Dicke radiometer employed in the design obtains tissue

temperature measurements noninvasively and operates by comparing an

internal reference temperature with an actual radiometric measurement

and using the difference to calculate body temperature. Early results show

the technique to be extremely accurate. Although radiometers have been

used for years in applications ranging from measuring atmospheric and

terrestrial radiation from space to oceanographic remote-sensing, the

radiometer designed by MMS incorporates several proprietary technologies

that optimize its use for cardiac ablation.

How did Microwave Offi ce software help deliver the solution?

Bob Allison, vice president and engineering manager at MMS, relied on

AWR’s Microwave Offi ce electronic design automation (EDA) software

along with a process design kit (PDK) developed jointly by AWR and

TriQuint Semiconductor that accurately represents TriQuint’s foundry

process. Allison has used AWR tools since their earliest development,

but his experience with EDA tools, as well as with virtually every other

high-frequency design solution, dates back to the days of mainframe time-

sharing. “I’ve found Microwave Offi ce to be unique among these tools for its

ability to make the design process comparatively simple,” says Allison. “It’s

created by engineers who understand the difference between designing a

microwave circuit and a digital one – and it shows in the software.”

How did the combination of AWR and TriQuint contribute to your

success? The seamless integration of Microwave Offi ce software and

the TriQuint PDK enabled Allison to design the circuit, select the features

from the PDK library, perform design rule checking, and send the result

to TriQuint, all in a very short time. “The handoff to TriQuint was utterly

painless,” said Allison. “Designing and producing our radiometer MMIC

with Microwave Offi ce and the TriQuint design kit provided an immense

productivity improvement. Measurements we’ve made on the devices we

received from TriQuint agree extremely well with the Microwave Offi ce

simulation. In short, we got back exactly what we hoped for.”

Microwave Offi ce simulation results agreed well with the actual measurements of the device.

AWRSuccessStory

AWR, 1960 East Grand Avenue, Suite 430, El Segundo, CA 90245, USATel: +1 (310) 726-3000 Fax: +1 (310) 726-3005 www.awrcorp.com

Copyright © 2008 AWR Corp. All rights reserved. AWR, the AWR logo and Microwave Offi ce are registered trademarks of AWR Corp. All others are property of their respective holders.

The radiometer MMICs of the catheter were designed by Microwave Offi ce software along with the TriQuint Semiconductor PDK.