Miguel VK3CPU - RF Inductor Calculator v1
Notes:
RF Inductor Designer was developed to help users predict the RF characteristics of a single-layer solenoid-style air-core inductor.
Inputs via the slider widgets:
- ⌀a : Conductor diameter in millimeters (mm).
- ⌀b : Loop diameter in millimeters (mm).
- c/a : 'c' is the inter-winding spacing, and 'a' is the conductor diameter, so 'c/a' is the spacing ratio. (Must be >= 1.1)
A low-value will increase the proximity effect.
- N : Number of turns or windings.
- f : The frequency of interest for some of the calculations.
Characteristics on the left are independent of frequency, while the characteristics on the right are dependent on the selected frequency.
Each of the graphic representations attempt to keep the relative geometry correct, without exceeding the drawing boundary. The coil diameter
relative to the conductor diameter are representative.
- Inductance is calculated using an equation incorporating the Nagaoka coefficient.
- Capacitance is calculated using Knight's 2016 paper on self-resonance and self-capacitance of solenoid coils.
- DC resistance is calculated using conductor length divided by the conductor cross-sectional area, assuming a copper conductor.
- Proximity resistance is calculated using the empirical data collected by Medhurst using the spacing ratio, and length-to-diameter ratio.