Capacitors and radio frequency generators and other devices using them

A mass filter comprising:

• a multipole assembly comprising a first pole, a second pole, a third pole and a fourth pole;
• a radio frequency generator electrically coupled to each of the first pole, the second pole, the third pole and the fourth pole of the multipole assembly to provide a radio frequency voltage to each of the first pole, the second pole, the third pole and the fourth pole, the radio frequency generator comprising a feedback circuit comprising a capacitor, in which the capacitor comprises:
• a first dielectric layer comprising a coefficient of thermal expansion of 15 ppm/deg. Celsius or less;
• a first electrode layer comprising an integral, solid material, wherein the first electrode layer comprises a coefficient of thermal expansion of 15 ppm/deg. Celsius or less;
• a second dielectric layer, in which the first electrode layer is positioned between the first dielectric layer and the second dielectric layer, wherein the second dielectric layer comprises a coefficient of thermal expansion of 15 ppm/deg. Celsius or less;
• a second electrode layer spatially separated from the first electrode layer through the second dielectric layer and comprising an integral, solid material, wherein the second electrode layer comprises a coefficient of thermal expansion of 15 ppm/deg. Celsius or less;
• a third dielectric layer, in which the second electrode layer is positioned between the second dielectric layer and the third dielectric layer, and wherein a coefficient of thermal expansion of the third dielectric layer is 15 ppm/deg, Celsius or less;
• a third electrode layer spatially separated from the second electrode layer through the third dielectric layer and comprising an integral, solid material, wherein the third electrode layer comprises a coefficient of thermal expansion of 15 ppm/deg. Celsius or less;
• a fourth dielectric layer, in which the third electrode layer is positioned between the third dielectric layer and the second dielectric layer, and wherein a coefficient of thermal expansion of the fourth dielectric layer is 15 ppm/deg. Celsius or less;
• a fourth electrode layer spatially separated from the third electrode layer through the fourth dielectric layer and comprising an integral, solid material, wherein the fourth electrode layer comprises a coefficient of thermal expansion of 15 ppm/deg. Celsius or less;
• a fifth dielectric layer, in which the fourth electrode layer is positioned between the fourth dielectric layer and the fifth dielectric layer, and wherein a coefficient of thermal expansion of the fifth dielectric layer is 15 ppm/deg. Celsius or less;
• wherein the first, second, third and fourth electrode layers are mechanically held against and between adjacent dielectric layers, wherein the first electrode layer and the fourth electrode layer are positioned to shield the second electrode layer and the third electrode layer from stray capacitive energy, wherein the adjacent dielectric layers are coupled to each other at outer edges, using an epoxy material comprising a coefficient of thermal expansion of 15 ppm/deg. Celsius or less, to hold the capacitor together, and wherein electrode terminals for each of the second electrode layer and the third electrode layer are present on a first side of the capacitor to electrically couple the second electrode layer and the third electrode layer to the feedback circuit through the terminals on the first side of the capacitor, and wherein electrode terminals for each of the first electrode layer and the fourth electrode layer are present on the second side of the capacitor to electrically couple the first electrode layer and the fourth electrode layer to the feedback circuit through the terminals on the second side of the capacitor.