Abstract
The feasibility of multi-frequency-band operation was studied using a finite element method simulator with respect to the authors proposed bottom mounting type isolator whose size is only 1/5 of the world smallest commercialized isolator in volume. The bottom mounting type isolator was found to exhibit practically usable non-reciprocal transmission characteristics in a wide frequency range from several hundred MHz to 5 GHz without change in the size of the isolator by changing bias magnetic field. Bias magnetic field control system composed of electromagnet, magnetic core and soft magnetic disk was proposed. It was found that the bottom mounting type isolator equipped with the bias magnetic field control system operates frequency range including 460 and 750 MHz bands planned for 4th generation mobile communication systems.
