- A well-known method for range applications is chirped frequency modulated continuous wave (FMCW) radar. We offer a simple way to measure the distance to the object target with high resolution based on very inexpensive glow discharge detectors (GDDs) at terahertz (THz) band frequencies. Proof of concept of THz FMCW radar using a GDD is experimentally demonstrated in this paper. The advantage of FMCW in the THz band is its better range resolution compared with FMCW radar in the microwave band due to wider frequency swing. Such a system using a GDD has the following advantages: very inexpensive and simple to realize, rigid components, room temperature operation, fast response time, and high power radiation immunity. Those properties are very important in the realization of high resolution 3-D imaging in the THz band. Depth resolution on the order of 7.5 mm can be achieved by the proposed system.