gamma matching
时间：04-09
整理：3721RD
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I am currently doing a project on RFID antenna design. Recently, i have been looking at doing GAMMA matching for my copper tape antenna. After being stuck at it for one week, i am still unable to get it right. Therefore, i would like to seek advice on anyone who has attempted GAMMA matching for RFID systems. The frequency that i am working on is 13.56 MHz.
Some steps that i have done so far are:
1)Making use of a LCR meter to measure the inductance of the antenna loop for my copper tape. Measured value obtained is 5 uH
2)Upon measuring the inductance for my antenna loop, I proceeded to make use of the formula C_RES=1⁄(ω^2 L) to calculate for the value of the capacitor needed to form a resonant circuit with my wire loop at a frequency of 13.56MHz.
Calculated Cres is 27 pF.
3)After that, I proceeded to calculate for the Rpar by using the formula R_par=2πfLQ.
4)The resultant circuit that I obtain is shown as below
Upon fixing up the resultant circuit, i connected the BNC connector to the Network analyser to check for the S11. However, the waveform that i obtained was distorted and didnt even have the usual dip. Therefore, i suspect that there is something wrong with my circuit (if the capacitor value that i have attached is wrong, i should still be able to get my waveform). I tried on my part to refer to the Texas instrument notes that i have attached in my post. However, the notes seems too brief for my liking. :(
Would be glad if anyone can help me out on this. Thanks!
Some steps that i have done so far are:
1)Making use of a LCR meter to measure the inductance of the antenna loop for my copper tape. Measured value obtained is 5 uH
2)Upon measuring the inductance for my antenna loop, I proceeded to make use of the formula C_RES=1⁄(ω^2 L) to calculate for the value of the capacitor needed to form a resonant circuit with my wire loop at a frequency of 13.56MHz.
Calculated Cres is 27 pF.
3)After that, I proceeded to calculate for the Rpar by using the formula R_par=2πfLQ.
4)The resultant circuit that I obtain is shown as below
Upon fixing up the resultant circuit, i connected the BNC connector to the Network analyser to check for the S11. However, the waveform that i obtained was distorted and didnt even have the usual dip. Therefore, i suspect that there is something wrong with my circuit (if the capacitor value that i have attached is wrong, i should still be able to get my waveform). I tried on my part to refer to the Texas instrument notes that i have attached in my post. However, the notes seems too brief for my liking. :(
Would be glad if anyone can help me out on this. Thanks!
my bad...my LCR meter can only measure up to a certain inductance value.
Manage to get my centre frequency at 13.56MHz after using a better LCR meter to do my measurements.