Coil Development Calculator Single Loop Resonator Surface Coil

Step 1

Get a first aproximate inductance for your loop using an Inductance Calculator. Here is a helpful inches/meters converter (no fractions allowed):

Inches =

(in)

Meters =

(m)

Step 2

Find the needed value of capacitance at each break in the loop by entering your loop's aproximate inductance, your desired resonanting frequency, and the number of breaks in the loop. (note: 1x10^{-7} may be entered as 1e-7). The number of breaks in the loop does not include breaks due to traps and/or matching/coupling capacitors. Build the loop with the specified capacitance.

Aproximate Inductance L =

(H)

Desired Frequency f =

(MHz)

Number of breaks =

Overall Capacitance Needed

= 0
(pF)

Capacitance needed at each break*

= 0
(pF)

Step 3

Input the value of capacitance used at each break. Analyze the loop on a network analyzer. Observe the current frequency that the loop is resonating at. Make sure you have the number of breaks set correctly from step 2. Using the observed frequency and the value of capacitance that you used, re-calculate the aproximate inductance of the loop. Insert this new aproximate inductance into step 2, using the desired frequency, to get a better aproximation for the value of capacitance needed. Re-build your loop with new capacitors. Iteratively go between steps 2 and 3 until your observed frequency is what you want it to be.

Capacitance used at each break

=
(pF)

Overall Capacitance Used*

= 0
(pF)

Observed Frequency f =

(MHz)

New Aproximate Inductance L =

0
(H)

*Capacitance at each break assumes equal capacitances in series.

**Calculations based on the equation: 2pi*f = 1 / sqrt(LC)

***Note, actual inductance of the coil varies only slightly with the changing of capacitors.
A large amount of the variation each iteration comes from the differing tolerances in the
capacitors. Once an initial inductance is determined to give a good idea of what initial
size capacitors should be used, this entire iterative process could be done without inductance
figuring into the equation at all. However, because of the equation** used, using inductance in
the iterative process makes no difference in the end. It is included in this calculator for
the secondary purpose of letting you know aproximately what your inductance is should that
information be useful to you.