Question

• • CP Cell phones that use 4G technology receive signals broadcast between 2 GHz and 8 GHz. (a) If you want to create a simple L-R-C series circuit to detect a 4.0 GHz cell phone signal, what is the relevant value of the product LC, where L is the inductance and C is the capacitance? (b) If you choose a capacitor that has C = 1.0 x 10–15 F, what inductance do you need? (c) Suppose you want to wind your own toroidal inductor and fit it inside a box as thin as your cell phone. Based on the size of your phone, estimate the largest cross-sectional area possible for this. (d) Assume the largest allowable radius of the toroid is 1.0 cm and estimate the lowest number of windings needed to create your inductor, assuming the material inside has a relative permeability of 1.

Answer 1

f = 4 GHz RLC for cirmir to zkusite Leia mziz = 0.001584 x 10-18 = 1.5BX107 10-21 it c= 1xio's . Sex102 - 1.5810-6H Ans IX 10-15 c) it thickness alan phones radius : 650 cu . LX2Txr Lilo NA 258 AL- Mon? larger cross sectional area ało? 3.14% -52x104 = 0.785 au? An

d) it 8=lan 1.58x10-6 Mon? A aar : N2= 1'50x10-682x374 X 102 Tax 10-7 X X x 10-4 0.25% 104 = 2500 Ne 50 Ans