Variable pitch and variable radius inductor coil designs within an aerosol-generating device

An aerosol-generating device, comprising:

• a housing defining a chamber configured to receive at least one susceptor and at least one aerosol-forming substrate, the chamber having a length along a longitudinal axis thereof extending from a first end of the chamber to a second end of the chamber;
• and
• an inductor coil provided within the housing, disposed around the chamber, and extending along at least a portion of the length of the chamber,
• wherein the inductor coil comprises a first portion disposed closest to the first end of the chamber, a second portion disposed closest to the second end of the chamber, and a third portion disposed between the first and the second portions,
• wherein a number of turns per unit length in the third portion of the inductor coil is at least 2 times smaller than a number of turns per unit length in one or both of the first and the second portions of the inductor coil,
• wherein a length of the first portion of the inductor coil as measured along a longitudinal axis of the inductor coil is substantially equal to a length of the second portion of the inductor coil as measured along the longitudinal axis of the inductor coil, and
• wherein the number of turns per millimeter length in the third portion of the coil is between about 0.25 and about 0.5.