Receiving filter of a saw separator with greater electrode interdigitated width in first stage parallel resonator

A receiving filter that is used in a SAW separator and comprises a ladder type filter, wherein

• said ladder type filter has plural stages of series arms and parallel arms wherein each of input side stages thereof is a first stage and each of output side stages thereof is a last stage,
• each of said series arms and parallel arms comprises a SAW resonator,
• said parallel arm at the first stage comprises one SAW resonator as a parallel arm resonator, and
• interdigitated width of said finger electrodes of said parallel arm resonator is greater than interdigitated width of finger electrodes of each of said parallel arm resonators at other stages.

A receiving filter that is used in a SAW separator and comprises a ladder type filter, wherein

• said ladder type filter has plural stages of series arms and parallel arms wherein each of input side stages thereof is a first stage and each of output side stages thereof is a last stage,
• each of said series arms and parallel arms comprises a SAW resonator,
• said parallel arm at the first stage comprises a series circuit of plural SAW resonators,
• the number of pairs of finger electrodes of each of said plural SAW resonators at the first stage is greater than the number of pairs of finger electrodes of each of said parallel arm resonators at other stages, and
• an interdigitated width of said finger electrodes of each of said plural SAW resonators at the first stage is greater than an interdigitated width of finger electrodes of each of said parallel arm resonators at other stages.

A receiving filter that is used in a SAW separator and comprises a ladder type filter, wherein

• said ladder type filter has plural stages of series arms and parallel arms wherein each of input side stages thereof is a first stage and each of output side stages thereof is a last stage,
• each of said series arms and parallel arms comprises a SAW resonator,
• said parallel arm at the first stage comprises a series circuit of plural SAW resonators, and
• an interdigitated width of said finger electrodes of each of said plural SAW resonators at the first stage is greater than an interdigitated width of finger electrodes of each of said parallel arm resonators at other stages.