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Prof UbicDr. Ubic’s research interests are in structure-property relationships in mirowave dielectric materials, empirically modeling the structural effects of defects in perovskites, hybrid organic-inorganic perovskite-based solar cells, and defect evolution in nuclear graphite.  His background is in materials science, and his principle expertise is in materials chemistry and structural characterization, especially electron microscopy and x-ray diffraction. He has received more than $4.6 million in research funding as PI from a variety of sources, and he has given dozens of invited/plenary/keynote presentations at international forums in 11 countries across four continents.

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Microwave Dielectric Resonators

On 3 April 1973, Martin Cooper, an executive at the fledgling Motorola company, stood on a street corner in Manhattan and tested his invention by calling rival AT&T to announce his breakthrough. In 1978, the world’s first experimental analogue mobile phone service was developed in the USA. Of course, the earliest mobiles were analogue, weighed almost 1.4 kg, had a battery life of less than a day, and sold for several thousand dollars. Eventually, phones shrank and evolved into what we see today. WAP phones were introduced in 1999, and the first camera phone entered the market in 2000, the same year that the first device marketed as a “smartphone” (Ericsson R380) was released.  Apple launched its iPhone in 2007, and the first Android device (HTC Dream G1) came out almost a year later.  Today, there are more mobile phone subscriptions in the USA than there are people, and the latest generation of phones weigh as little as 150g and offer features like Internet access, GPS, streaming, etc.

Worldwide there are currently about 4.1 billion mobile phone users, making the cellular phone the fastest-selling consumer item in history. The mobile phone is the most widely-spread technology on the planet. There are three times as many mobile phones than PCs of any kind in the world and more mobile phones than cars. There are over twice as many mobile phone users as internet users, and more mobile phone users than people with a credit card. Twice as many people use SMS text messaging worldwide than use e-mail, with 75,000 messages sent every second in the USA!

Microwave resonators are used extensively in telecommunications equipment, including cellular telephones and satellite links, and are at the heart of this multi-billion dollar market. Oxide ceramics are critical elements in these devices, and a full understanding of the crystal chemistry of such materials is paramount to future development.

Download Dielectric Software

image of Hakki-Coleman graphicHakCol
Calculates the relative permittivity of a post resonator tested in Hakki-Coleman
(or Courtney) parallel plates (TE011 mode), given the resonant frequency and geometry.

Calculates the relative permittivity of a dielectric-rod waveguide (TE01d mode).

Recommended reading before running the above programmes.

Calculates the Bessel functions involved in these equations.

Calculates the Gamma function which can be used in the solution of Bessel functions.

Download Crystallographic Software

Calculates the inter-planar spacings, angles, and twin-related reflections of any crystal structure.
Calculates the structure factors and full x-ray diffraction pattern for any crystal (beta version – not all elements supported).

Last updated 30-July-2018 14:34