A Driver IC & a Beginners question about overloading

Dear Geeks,

I ve little knowledge about RF...

I ve a simple doubt may be its silly..but i dont really know the answer

Q. I ve a RF driver IC it is capable of maximum power output of say 5dBm (output impedance 100Ohm). Im using this IC to drive a load.. But the problem with the load is it is not perfectly matched to the driver IC output impedance..it will vary over the frequency..

Say i simulate the load impedance using Agilent ADS.. when S11 is plotted it is showing impedance like 48+j70 etc..

What i need is the effective impedance to remain at 100Ohms ..

so my doubt is how will i calculate the effective impedance of 48+j70 ?

shall i look at the real part only ?
or shall i convert it to polar form z=a+ib , |z|=^/a2+b2; and theta= tan inverse(b/a)..?

Thanks for any help,

Use SmithChart to match the the load to 100 ohms. For a bandwidth, make the matched impedance circle near the center of the smithchart.