Pinhole device: a new type of thin film transformer

A novel type of thin film transformer was fabricated using a strip line, an amorphous CoNbZr film, and a ground plane. This thin film transformer has three small pinholes in the magnetic film. The strip line was terminated to the ground plane through the hole. This is called a pinhole device. The output voltage increased with increasing excitation frequency. Applying a DC magnetic field decreased the output voltage above 800 MHz, and increased it below 800 MHz. It is concluded that the pinhole device can be used as a controllable transformer at very high frequencies.>