Projects

The LLRISE radar is a simple FMCW radar operating at 2.4GHz, which is used to teach students how radars work and give some hands-on experience.  Part of my job at Lincoln lab was to redesign the radar to significantly reduce the BOM cost by making a separate RF board with SMD parts, instead of using connectorized ones from mini-circuits.   I also redesigned the sweep generator and digitization, to use an ARM microcontroller with an internal ADC and DAC instead of analog signal generator and microphone input on a laptop.  Between these and a few other changes to the design, the cost dropped from around $450 to $100, and significantly improved performance of the IF section.

Keeping the RF board, with its stricter requirements and more difficult SMD soldering, separate from the IF board, allowed a common RF section to be used on multiple versions of the IF section, of which I made two.  One was optimized for size and cost, and to allow the whole system to be folded into a smaller space.  This used SMD parts, and a more compact connector arrangement.  The second board was optimized for simplicity and to be easy for students, most of who had never soldered before, to assemble by using large, through hole parts.

Another goal of the project was to simplify the physical construction.  The previous design was very large and entirely 3D printed, which was expensive, slow to make, and occupied the lab printers for a long time for each.  A The new design has only five printed parts, which use very little filament and can be printed very quickly with no support.  The remaining parts are laser cut, which was chosen as it is significantly faster and cheaper for large components.  The assembly can also be performed in less than five minutes with no tools, where the previous design would often take several hours.