I took antenna theory in college for a couple years and then worked in the automotive field designing in-glass antenna systems for cars in the 1990s for a few y

I took antenna theory in college for a couple years and then worked in the automotive field designing in-glass antenna systems for cars in the 1990s for a few years. It has been a few years but reading the article I couldn't help but recall some of my college courses and how I was able to apply some of what I learned in college to the state of the art at the time. We use to have to drive cars by a local glass company to have the rear window removed and taped back in until I got to the office. Once at the office I would lay the glass on a metal frame and layout an antenna using gold conducting tape. Put the windshield back into the car and blast it with network spectrum analyzer. Antenna's have both a theoretical wave length and an actual wave length as measured through the medium you're radiating from. We had loads of conduit in our work shop so one day I managed to grab a couple pieces of conduit and made some rough back of the napkin calculations to convert the theoretical wave length to an actual wave length for metal conduit. My work was for AM and FM radio in the 88-108MHz. One day a customer comes into the office who knew me well from many visits and saw me hack sawing a piece of conduit with a wire hanging off the side. He asked what I was doing and I told him I was calibrating an antenna. We were a start up so we had to make due with stuff lying around. I couldn't help but read the article and wonder how the dielectric mentioned would effectively shorten the wavelength. Wave length in a medium can be thought of the effort to push back and forth the electrons to radiate. Another analogy is it's easier to wave your hand in air than it is in water; water being akin to the dielectric. A dielectric with 60% efficiency seems more material science than electrical engineering. Interesting work. Curious what materials they use or perhaps going to higher frequencies.