RF Coil Design... VE3KL

Input Data [See Diagram Below]

Frequency [MHz] Coil Diameter [mm] Wire Diameter
Coil Pitch
Number of Turns [Integer] Select Wire Material

This area is optional. Use for Insulated Wires

Insulator Thickness [mm] Insulator Relative Dielectric Constant

Coil Length [mm]
Wire Length [mm]
Low Frequency Inductance [uH]
Coil Q
Resonant Frequency [MHz]
Total Capacitance [pF]
Reactance at Operating Frequency [Ohms]
Resistance at Operating Frequency

Coil Description

The analysis applies to an air wound coil that is constructed from either bare or insulated wire.

The dimensions of the coil are its diameter, pitch, wire diameter,insulator thickness and length. The length is given by the number of turns times the pitch. The wire material can be selected from a set of commonly used metals ranging from Silver to Bronze.

What the Calculator Does

The calculator computes most of the important electrical amid physical properties of the coil after the user defines input data.

The Input Data is:
Frequency, Coil Diameter, Wire Diameter,Coil Pitch, Number of turns, wire material, insulator material and insulator thickness.

The Output Data is:
The Coil length, wire length, low frequency inductance, Quality Factor Q, resonant frequency , Coil capacitance, Reactance at the operating frequency and Coil resistance at the operating frequency.

How to Use the Calculator

First, input the main data in the first box starting from the frequency and ending with a selection of the wire material. Note that the number of turns must a positive integer (not a decimal number such as 5.7). This is limitation of the calculator algorithm. Also note that the pitch will normally be set to zero for a single turn coil but this is not necessary.

Be careful to set the pitch properly. The pitch must be greater than the wire diameter plus twice the insulator thickness.

Second, use the optional area to input the wire insulation thickness and relative dielectric constant is you are using insulated wire. If PVC is used for the insulation, its dielectric constant is approximately 2.3. Other material used for wire insulators such as polyurethane have a dielectric constant between 3 and 5.