How does RF Coax cable impedance + Microstrip impedance mismatch affect power transfer
You will lose some power, but probably not an unacceptable amount - especially if the input of the receiver is in the 40 to 50 Ohm range.  I get a gamma of -0.19 for coax to ms which is less than 0.2 dB power xfer loss - not the end of the world :).

However if the receiver input were, say 100 ohms, you'd get a gamma of about 0.5 there and lose 1/4 of your power.