- #1

amanno

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**Inductive Square Antenna Coil**that will be milled onto my PCB. I am slightly confused when it comes to the matching circuit. To my understanding the matching circuit is there to have the same impedance value of the antenna, correct?

So my matching circuit consist of capacitors such that X

_{L_ant}= X

_{C_tun}, correct?

When I calculate the inductance value of my designed antenna I get a value around 980 μH, which makes X

_{L}= ~83kΩ (f = 13.56 MHz). That just seems very high to me, I thought antennas were suppose to have an impedance of ~50 - 75 Ω.

My coil antenna has the following properties:

K

_{1}= 2.34, K

_{2}= 2.75

d_out = 33 mm

d_in = 17mm

N = 4

and I am using the equation below to calculate the inductance

L

_{ANT}= K

_{1}× μ0 × N

^{2}× (d / (1 + K

_{2}) × p)

I have tried playing with the properties of my designed antenna to reduce the impedance but I can't seem to bring it down low enough, which makes me think I am missing something.

Any help/guidance would be greatly appreciated! Thanks.