I've been playing with some Loop Antennas and have ideas for some small receiving loops. These fit the model of a single-layer inductor, or solenoid, type of inductance.

For more research, see (pdf): R. Lundin, "A Handbook Formula for the Inductance of a Single-Layer Circular Coil", Proc. IEEE, vol. 73, no. 9, pp. 1428-1429, Sep. 1985.