Five novel ideas are proposed for integrating an active radio frequency identification (RFID) tag with a thermal convection angular accelerometer on a flexible substrate. The first two ideas are to fabricate the device directly on a flexible substrate (e.g., polyimide) and without any movable parts. The flexible substrate thermal conductivity is much lower than that of silicon, so the new substrate can save more power and be very reliable. The third idea is to apply xenon gas in the chamber for heat convection instead of the traditional carbon dioxide, so that the heater and thermal sensors have no oxidation and performance degradation effects. The fourth idea is to integrate the angular accelerometer with an active RFID tag on the same substrate; thus, the device becomes a more useful wireless sensor. The final idea is to apply a hemispherical chamber instead of the conventional rectangular one to increase the sensitivity and response speed of the angular accelerometer. Although both sensitivity and response speed are lower than those of the floating one, the nonfloating device may be a choice if reliability and cost are the major concerns. Moreover, for the angular acceleration lower than 75 deg/s2, the sensitivity [0.2 K/(deg/s2)] and response speed (693 μs) are better using a hemispherical chamber than using the conventional rectangular one [0.167 K/(deg/s2) and 1183 μs].