http://www.digitaljournal.com/tech-and-science/science/making-microwave-technology-much-cheaper-and-better/article/523185

Making microwave technology much cheaper and better

Posted May 26, 2018 by Tim Sandle
A Canadian-led breakthrough with silicon materials could lead to microwave technology becoming far cheaper and to perform better.
Camera and microwave transmitter for wireless long range audio and video surveillance
Camera and microwave transmitter for wireless long range audio and video surveillance
Digital Journal
Scientists from the University of Waterloo have taking advantage of supercomputing to find an improved means to generate microwaves. This is with inexpensive silicon. The technological breakthrough could significantly lower the costs of generating microwaves and improve the functionality of devices reliant upon microwave technology, such as the sensors fitted within self-driving vehicles.
Microwaves are key to many advanced and emerging communications technologies. Here, high-frequency microwaves send signals across a wide range of devices. Applications include the radar units police use to assess speeding motor vehicles, as well as the collision-avoidance systems that are vital to autonomous vehicles.
These microwaves are generated using devices called Gunn diodes. The diodes are based on the properties of expensive and toxic semiconductor materials like gallium arsenide (a compound of the elements gallium and arsenic). Gunn diodes (or transferred electron devices ) are types of diodes which function as two-terminal passive semiconductor electronic components. They are essential to high-frequency electronics
As voltage is applied to gallium arsenide and increased, the electrical current running the compound also increases to a certain point; after this the current decreases, leading to the emission of microwaves.
Seeking improvements, the researchers used computational nanotechnology to demonstrate that the same effect could be achieved with silicon. The advantage is that silicon is more abundant and far cheaper than gallium arsenide. Moreover, the use of silicon allows for smaller structures to be devised and ones that are more efficient.
The study has been reported to the journal Scientific Reports. The research paper is called "Gunn-Hilsum Effect in Mechanically Strained Silicon Nanowires: Tunable Negative Differential Resistance."