detect handphone

dear all,

i just wonder, would it possible if i want to design a antenna which can detect a hand phone signal(for example,making call,received call or sending SMS?). i understand,our Hand phone will transmit or emit an amount of electromagnetic signal, but would it practical to use helical antenna to detect it? if no, what is alternative best solution to detect the electromagnetic signal. besides ability to detect, it shoudl be low cost and able to be differenttiable with others noise interference signal.

any ideas ?
any guide or suggestion taht i can use for reference~

best regards