Features of dual-frequency passive devices design for the radio channel of wireless access systems

The questions of realization of dual-band passive microwave devices for a radio channel of wireless access systems are considered in the report.The execution possibility of dual-band front-end module for WiFi connectivity on the basis of such dual-band schemes is shown on the example of real module. A number of main passive elements on which depends the dual-band work of system are defined and options of their realization, as well as the approaches to development of methods for their calculation are considered. In particular, the methods of calculation of asymmetrical and symmetric dual-frequency impedance transformers are offered. Further, the way of the dual-frequency SPDT switch implementation with use of such transformers is specified. Also it is said how to use the symmetry of structure of the directional couplers, hybrids and dividers for calculation of their parameters at dual-frequency operation. For development of dual-bandpass filters it is offered to use the modified variant of the well-known single-frequency filter by the adding of reactances to resonators.