Research Interests

Research Interests and Achievements

Professor Katehi is an expert in the areas of development and characterization (theoretical and experimental) of microwave, millime­ter printed circuits; the computer-aided design of VLSI interconnects; the development and characterization of micro-machined circuits for microwave, millimeter-wave and sub-­millimeter-wave applications including MEMS switches, high-Q evanescent mode filters and MEMS devices for circuit re-configurability; the development of low-loss lines for sub-millimeter-wave and terahertz frequency applications; theoretical and experimental study of unipla­nar circuits for hybrid-monolithic and monolithic oscillator, amplifier and mixer applica­tions; theoretical and experimental characterization of photonic band-gap materials.

The most important contributions of here work are:

The development of novel three-dimensional integration along with on-wafer packaging schemes

Katehi has been a pioneer in studying high-frequency effects on planar circuits and understanding parasitic radiation, substrate-wave propagation, and the importance of high-frequency parasitic phenomena on the performance of planar circuits. Her work demonstrated that 3-D integration is the approach to achieve high performance in high frequencies. In pursue of fully integrated three-dimensional circuit architectures and on-wafer packaging, she explored for the first time the use of Si-micromachining in circuit design.

Katehi developed three dimensional circuit integration architectures and on wafer packaging that have been adopted by DoD and the defense industry as the architecture for the next generation of high-frequency circuits. Based on Katehi’s work DARPA funded four major research and development programs, MAFET III, IRFFE, MERFS and SMART, of a total of $200M to demonstrate 3-D circuit architectures on receive and transmit systems operating between 2Ghz and 94GHz. Furthermore, the defense industry is now using the architectures pioneered by Prof. Katehi to develop the RF front ends of the next generation of military sensors such as XG, JTRS, GPS-Guided Munitions. Specifically, Lincoln Labs and Northrop Grumman have adopted the on-wafer packaging for RF MEMS which was demonstrate by Katehi’s work and Raytheon and Rockwell Collins used these three-dimensional interconnects for their reconfigurable high-frequency RF systems. Prof. Katehi’s foundamental designs have been incorporated in the development of new systems worth a total of  $1B-$10B in the defense economy and due to substantial gains in size and performance have provided savings of many hundreds of million of dollars in the cost of these systems.

The first demonstration of a membrane-supported interconnect for operation from dc to 500GHz along with non-invasive vector-wave measurements of near fields

This work led to the development of novel filters for terahertz frequencies and embedded high-Q filters high-Q filters (Q>3,000) and inductors (Q>100) for operation up to 100 GHz. This work was further extended to demonstrate the first on-wafer package for high-frequency membrane circuits including RF MEMS switches and introduced the concept of heterogeneous wafer integration in high-density 3-D interconnect networks. She performed pioneering work to demonstrate through the DARPA funded “94GHz Power-Cube” that 3-D circuit integration is superior to the 2-D and provides answers to low-power consumption at high frequencies. 

Fast Time Domain Methods for Application to High-Frequency Circuits

Prof.  Katehi has made  contributions  to  the  development  of  fast  time domain  methods for application to the solution of high frequency circuits. She was able to solve, for the first time, Maxwell’s equations for fairly complex boundary value problems using a new time domain method based on the use of Wavelets (multi-resolution expansions). This method, known as MRTD, is the first demonstrated time domain method in electromagnetics that allows for a time adaptive gridding in a mathematically rigorous way and consistent with the physical conditions governing the solution of the problem.


Commercialization of High-Frequency Tools

In addition to  her  scientific  and  engineering contributions, Prof.  Katehi has participated  in  considerable  technology  transfer. In December 1994, she started, as one of three owners, a company, which was built on her work on the modeling of high-frequency circuits and antennas using fast multi-resolution-based computational methods. Since 1994, EMAG Technologies, based in Ann Arbor MI, has employed more than 100 engineers and is commercializing the first high-frequency  circuit  and  antenna  software  with  extensive  design capability.  EMAG Technologies recently have recently commercialized NEOSCAN, a portable, electro-optic, fiber-based system for non-invasive vector near-field measurements.  This system is based on the work by Prof. Katehi’s group that was recognized in 1995 by the Microwave Prize of the IEEE Microwave Theory and Techniques Society.




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