Click here to go to go to our main page on microstrip
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Click here to learn about rubylithography
Microstrip is a planar transmission line, similar to stripline and coplanar waveguide. Microstrip was developed by ITT Federal Telecommunications Laboratories in Nutley New Jersey, as a competitor to stripline (first published by Grieg and Engelmann in the December 1952 IRE proceedings). According to Pozar, early microstrip work used fat substrates, which allowed non-TEM waves to propagate which makes results unpredictable. In the 1960s the thin version of microstrip became popular.
By 1955 ITT had published a number of papers on microstrip in the IEEE transactions on microwave theory and technique. A paper by M. Arditi titled Characteristics and Applications of Microstrip for Microwave Wiring is a good one. The author seems to apologize for the inability of microstrip to support slotted line measurements, (as it is "rather unconventional") and concludes that it is dispersion-free but non-TEM mode but admits that he didn't analyze this, he bases his assumption on limited measured data. The "microstrip kit" shown below is a priceless artifact. Presumably it would be sent to customers to let them try out microstrip for themselves. Networks such as rat-races can somehow be clipped together to form a receiver or something useful. It has plenty of transitions to waveguide and coax (called "transducers" in the paper) so you can actually measure what you just made... if anyone has one of these gems, please tell us your address we will fly the Microwaves101 private jet there to take some proper pictures!
This kit is similar to the Raytheon "Lectron", which was an educational toy marketed starting in 1967 in which magnets held circuit elements imprinted with their schematic symbols together, it had everything you needed to build a simple transistor radio, including a tiny speaker. One of these days we'll go out to the garage, find our old Lectron and take some photos. Not long ago, a Raytheon lawyer warned us not to use their good name on this web site. To which we respond, "ptttthhhhh!" with extra ejected saliva.
In 1996, a serious crime against microwave history was committed when ITT Nutley tore down their 300 foot microwave research tower to make way for some ugly condos, as shown in the video below. As a great receiver designer, ex-boss, musician and personal friend named Zvi used to say, "chicken today, fether pillows tomorrow".
ITT became a stepchild of Harris. Harris and L3 merged to form L3Harris in June 2019. Click here to learn more about where other microwave nameplates are now.
The history of microstrip should include a review of ruby-lithography, and Bedford Automated Artwork.