Conventional Thermo-Time Domain Reflectometry (TTDR) sensors can be used to estimate soil bulk density under controlled settings, but can be unreliable in the field.  Deflection of the sensor needles can cause inaccurate estimations of soil thermal properties which in turn affect soil density calculations.  A new geometry was developed to produce a sensor more suited to demanding field applications.  Two opposing curved blades were used as the TDR wave guides and also supported the heaters.  A needle located centrally between the blades contained a thermistor used to measure temperature rise and determine the soil thermal properties.  This paper describes the theory, construction, calibration, validation, and field tests of the sensor.  The improved sensor design greatly reduced the sensitivity to needle deflection for more accurate thermal property measurements.  It also facilitated longer wave guides for improved TDR accuracy.