How can I control the impedance of the spiral antenna?

Dear all

I am a student and i am trying to design 2 arm archimedean spiral antenna@60GHz in HFSS 10.

however the simulation result of s11 can not be satisfied.In hfss design, i put lump port in center of spiral, between 2 spiral arms.I want to match it with coaxial 50 ohm.

so how can I control the impedance of the spiral antenna.(How to reduce that imaginer and decrease that real)

thank you for helping me...
Best regards

The spiral antenna usually has an impedance to
about 150 to 200 Ohms. It is intrinsically that way.
Most people just design a matching network for
a 50 Ohm cable.

Hello jallem

First Thank you for your reply.

I want to design a spiral antenna to operate as filter and antenna.(and the size of it is limited)so I can not use matching network.

Is there any way else to change its impedance ?

Thanks.