tem mode coaxial

how to model it in ads or at least get it's equivalent circuit
please respond fast
here is it's photo
http://www.techworld.co.kr/buyersgui..._image/TEM.jpg

U can't. You need a 3 D simulator. Try either HFSS or CST design studio.

I do not remember the exact model, so you will have to get one, test it, and modify to curve fit, but roughly these operate like short circuited transmission lines of an impedance in the 5-10 ohm range with dielectric constant in the (I really don't remember) 20 to 50 range.

Just hook up a 1 pf series, this resonator in shunt, and a 1 pf in series out, measure the bandpass, and tweak the modely.