Microelectronics startups design things that use microelectronics (think circuit boards). The items can be things such as RC cars, cell phones, computer circuitry.
Some startup specifics
The development of microelectronics can be difficult to do manually for complicated boards. There is software but some say that the tools are not good enough. There are good enough tools but they are thousands of dollars.
It costs money to prototype and for complex things it is going to cost a lot more to prototype.
Production can be difficult because most microelectronics are produced in Asia. The manufacturers over there are widely known to copy designs and sell the knockoffs. The IP law there is also pretty lax in effectiveness so they are able to manufacture the items and then sell them anywhere they want to.
A way to get around this is to create 2 circuits that connect with a tether. Then you send each half to two different manufacturers. This way neither has the full design.
Marketing new electronics because difficult without the proper niche wants. For instance gaming peripherals, IT community (e.g. routers and switches). The medium to market in is going to be mostly online. Not a lot are shown on the TV or any other ways. Also it is difficult to sell your digital item if you don’t have a good brand name or some really powerful selling point. People are very finicky about their electronics as there are so many options to choose from.
The FCC is in charge of making sure electronics operate a certain way so that bad things don’t happen like leaking too much RF or breaking the laws like being able to tap into other peoples communications illegally.
It is difficult to fund an electronic device but is getting easier with crowdfunding platforms that like nichey and innovative products.