The lumped equivalent circuit model of the multi-passband tunable microwave magnetoelectric filters

Abstract

A magnetoelectric tunable microwave filter is proposed, which has multi-passband at corresponding frequencies when different magnetic fields are applied on multi-magnetoelectric laminates. A generalized lumped equivalent circuit model for the filter is established to predict the transmission characteristics. For existing experimental results of the microstrip filter with one magnetoelectric laminate put on the coupling microstrip lines, therefore the lumped circuit model is degraded. And the validity of the model is confirmed from the result that the predictions of the model are in good agreement with the results obtained by the electromagnetic simulation software and experimental results. Then, the performance of the multi-passband microwave filter with a plurality of magnetoelectric laminates is studied by the lumped equivalent circuit. It is found that any single band of multi-passband can be tunable through controlling the applied field on a block of magnetoelectric laminate, which can improve the practicability and flexibility of the bandpass filter. Moreover, when the same field is applied on the magnetoelectric laminates, the multi-passband will be combined into a single passband. The combined single passband has significantly larger bandwidth than the corresponding bandwidth of the filter, which has a single laminate with the same applied field, which can improve the bandpass effect obviously.