Abstract: A band pass filter comprises an air filled aluminum chamber, having a lid and a cuboid resonant cavity having a central iris. At opposite end nodes of the cavity, perfect electric conductors (PECs) are provided. One is connected to a feed wire from an input at one end of the cavity. The other PEC is connected via a further feed wire to a radiator in a fabrication of solid-dielectric, lucent material. Threaded tuning projections opposite the PECs and in the iris are provided, whereby the pass band and the transmission characteristics of the filter in the pass band can be tuned to match the input impedance of the band pass filter and the wave guide to the output impedance of a microwave drive circuit (not shown). Typically the impedance will be 50?.

Abstract: A plasma crucible has a through bore and two tubes butt scaled on to the end faces of the crucible. One of the tubes is closed prior to the filling of the crucible. The tube is tipped off and worked in a glass lathe to form it to have a flat end. After evacuation, dosing and gas fill, the other tube is tipped off in the similar manner.

Abstract: A band pass filter comprises an air filled aluminium chamber, having a lid and a cuboid resonant cavity having a central iris. At opposite end nodes of the cavity, perfect electric conductors (PECs) are provided. One is connected to a feed wire from an input at one end of the cavity. The other PEC is connected via a further feed wire to a radiator in a fabrication of solid-dielectric, lucent material. Threaded tuning projections opposite the PECs and in the iris are provided, whereby the pass band and the transmission characteristics of the filter in the pass band can be tuned to match the input impedance of the band pass filter and the wave guide to the output impedance of a microwave drive circuit (not shown). Typically the impedance will be 50?.

Abstract: A bandpass filter comprises an air filled aluminum chamber having a lid and a cuboid resonant cavity having a central iris. At opposite end nodes of the cavity, perfect electric conductors (PECs) are provided. Threaded tuning projections opposite the PECs and in the iris are provided, whereby the pass band and the transmission characteristics of the filter in the pass band can be tuned to match the input impedance of the band pass filter and the wave guide to the output impedance of a microwave drive circuit. It is mounted on one end of the filter chamber, with an electrodeless bulb in a central cavity directed axially away from the chamber and the radiator in a further cavity set to one side of the central cavity. When the filter is driven, the wave guide resonates driving the bulb.

Abstract: A plasma crucible has a through bore and two tubes butt scaled on to the end faces of the crucible. One of the tubes is closed prior to the filling of the crucible. The tube is tipped off and worked in a glass lathe to form it to have a flat end. After evacuation, dosing and gas fill, the other tube is tipped off in the similar manner.

Abstract: A bandpass filter comprises an air filled aluminum chamber having a lid and a cuboid resonant cavity having a central iris. At opposite end nodes of the cavity, perfect electric conductors (PECs) are provided. Threaded tuning projections opposite the PECs and in the iris are provided, whereby the pass band and the transmission characteristics of the filter in the pass band can be tuned to match the input impedance of the band pass filter and the wave guide to the output impedance of a microwave drive circuit. It is mounted on one end of the filter chamber, with an electrodeless bulb in a central cavity directed axially away from the chamber and the radiator in a further cavity set to one side of the central cavity. When the filter is driven, the wave guide resonates driving the bulb.