Abstract: A high frequency circuit includes a first insulating layer; a second insulating layer stacked on the first insulating layer directly or with one or more intermediate layers interposed therebetween; a first ground disposed on a first surface that does not face the second insulating layer among the first surface and a second surface forming two surfaces of the first insulating layer; a first line having a first end portion to which a first alternating-current signal is to be supplied and a second line having a second end portion to which a second alternating-current signal is to be supplied that are disposed between the first insulating layer and the second insulating layer; a second ground disposed on a third surface that does not face the first insulating layer among the third surface and a fourth surface forming two surfaces of the second insulating layer; and a first shield via.

Abstract: The roller-hearth continuous furnace of the present invention comprises a tunnel-shaped furnace housing provided with a larger number of rollers shielded from outside, the inside of the furnace being divided into a heating section, a soaking section and a cooling section in this order with the heating section located close to the inlet of the furnace housing. The cooling section has a means for feeding of atmosphere-controlling gas and a means for detection of furnace inside pressure. The heating section has a means for forced gas exhaustion, capable of sucking a furnace inside gas correspondingly to the furnace inside pressure detected by said means for detection of the pressure. The present roller-hearth continuous furnace having the above constitution ensures cooling in a stable atmosphere and can provide household or industrial ceramic wares of stable quality.