**5. Conclusion**

New pacemaker tends to integrate a wireless telemetry system to allow home monitoring of the patient. The quality of service is strongly improved with an increase of safety, comfort and a reduction of cost. However, this challenge faces to a number of limitations like the need of low power high efficiency design, the degradation of the budget link while the antenna is immersed into the human body, etc. Indeed, it is demonstrated that the antenna impedance changes while immersed into human body causing mismatch of the antenna. To avoid antenna mismatch and reduction of the power efficiency of the radio link, we have proposed a new method to automatically match the antenna impedance to the front-end radio. This method operates in a single step to extract the antenna input impedance value exploited by a processor to match the antenna to the front-end radio both in transmission and reception. A demonstrator operating at the MICS 402-405 MHz frequency band was fabricated and an experimental set-up was presented. This prototype calibrates the system in less than 900μs with a 40MIPS clock processor to achieve a coefficient reflection S11 up to -30dB.
