Apple's Airpods might kick start mainstream consumer interest in hearables. The devices look beautiful, they have a the might of a tech giant behind them, but how do you go about making something this small?
Understanding the RF, particularly the radio antenna design, is critically important. The size and shape of the hearable dictates the available real estate for the radio antenna. Conversely the size, shape and location of the antenna introduces constraints about where other components can be located inside the product. A good antenna will efficiently radiate all the bounded energy from the radio into air waves thereby requiring less energy to communicate and reducing the energy demand on the battery, which is typically the largest single component in the product.
To give an idea of the technical challenge, most antennas are efficient when their size is a quarter of half the operating wavelength. At 2.4 GHz, the wavelength is about 12.5 cm so a half wave antenna is about 6 cm. This is not something you want sticking out of your ear, unless (in the words of my colleague Robert Milner) you're going for the Frankenstein look. This is further complicated by the fact that the body absorbs much of the wireless signal.
But these challenges can be overcome. We apply our design insights from the extremely demanding challenge of communicating with implants and both the wearables and hearables markets. In implants we have patented techniques that use specific electromagnetic characteristics of the body to enhance Bluetooth transmission from miniature antennas (1/8th to 1/10th the wavelength). In doing so we meet performance levels unmatched in either academic or industry data. If you'd like to know more, my IEEE webinar on the development of smart medical implants is here