US 9,814,104 B2
Space-efficient choke system for containing RF leakage
Richard E. Hunter, Liberty Township, OH (US)
Assigned to ILLINOIS TOOL WORKS INC., Glenview, IL (US)
Filed by Illinois Tool Works Inc., Glenview, IL (US)
Filed on Jan. 27, 2015, as Appl. No. 14/606,223.
Prior Publication US 2016/0219656 A1, Jul. 28, 2016
Int. Cl. H05B 6/76 (2006.01); H05B 6/64 (2006.01)
CPC H05B 6/763 (2013.01) [H05B 6/6414 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An oven comprising:
a radio frequency (RF) source;
a cooking chamber into which RF energy is providable via the RF source;
a door configured to hingedly operate to alternately allow access to the cooking chamber and close the cooking chamber for cooking; and
a choke assembly disposed to seal a region between the door and walls of the oven that define the cooking chamber from RF leakage responsive to closure of the door,
wherein the choke assembly comprises:
a capacitive coupling element comprising a plurality of tabs each having a first width;
an inductive tuning element comprising a plurality of projections bent relative to the capacitive coupling elements at a right angle, the projections each having a second width that is smaller than the first width; and
a low impedance resonator and grounding element,
wherein the low impedance resonator and grounding element has a width extending in a direction parallel to a length of the inductive tuning element and substantially perpendicular to a length of the capacitive coupling element,
wherein a combined length of the choke assembly comprises the width of the low impedance resonator and grounding element, the length of the inductive tuning element and the length of the capacitive coupling element,
and wherein the combined length of the choke assembly for a given frequency is about 20% less than a combined length of a quarter wave resonant choke for the given frequency.