Help Needed in Patch Antenna for MTBF & MTTF

Hello Everyone! I was asked to design a Patch antenna for a GPS receiver. I was provided with all the design specifications like gain, impedance etc. I have designed that antenna in HFSS. Now I am asked to calculate the Mean Time to Failure (MTTF) & Mean Time Between Failure (MTBF) for that Patch Antenna. I really don't know how to calculate them. :( I have looked on google but I just saw some definitions. Can anybody help me in this matter? I shall be very grateful.

Getting data on passive components is quite difficult. Try google MIL standard on reliability of electronic components. A patch antenna in my opinion can be considered a part of a plastic case, so its reliability may be considered similar to the case. Only mechanical damage is possible.
Semiconductor components are much less reliable and their MTBF is a function of junction temperature. The referred MIL standard lists MTBF of selected components.
Not many component makers include MTBF data of their components. Mini-Circuits is an exception.

There are lifetime tests for electronic devices, but most of them deal with active devices other than antennas (which commonly is purely passive). Before planning the lifetime tests, u need to at least have a good guess of the failure modes of the device under test. For example, if there is soldering on the antenna, then the connection may be degraded due to temperature cycling. Then temperature cycling should be included in the lifetime test. Besides, u also need to define some criteria in order to quantitatively measure the performance degradation of the DUT. After completing the lifetime test, the lifetime can be estimated accordingly.