power divider and filter

Power divider:

A large class of microwave components can be formed by combining two phase shifters and two fixed power dividers (combiners). A power divider and a power combiner may be made to operate over broad frequency bands at relatively high RF power levels. In the field of RF transmission, power requirements may exceed practical levels for a single amplifier, making it desirable to amplify a signal with multiple RF power amplifiers in parallel. An input power divider circuit is used to divide the signal and provide it to the inputs of the multiple amplifiers, while an output combiner provides the combined outputs of the multiple amplifiers to the next stage load. Many applications involve circuits requiring two input power signals to be combined into one output signal to be operated on by following circuits. Radio frequency power combiners are used for combining a number of RF inputs into a single output in a transmission system. The combiner also prevent a high current flow in a short circuited failed radio frequency power source, this current being derived from the remaining operative radio frequency power sources. Power combining techniques for radio frequency signals, including millimeter wavelength signals, have been accomplished in either a waveguide circuit or in a microstrip circuit.

Filter:

A radio frequency (RF) filter is designed to be tuned to pass energy at a specified resonant frequency. In microwave communications systems, it is often necessary to filter a relatively broadband microwave signal into its component sub-bands. In order to combine a number of RF transmitters, the RF signals from each transmitter must be isolated from one another to prevent intermodulation and possible damage to the transmitters. RF filters of the air-filled cavity type may be utilized to provide isolation between the RF transmitters. High-frequency filters, such as RF filters, are used to implement high-frequency circuits in the base stations of mobile networks, mobile phones and other radio transceivers. Other RF filter applications include the adapter circuits and filter circuits of transmitter and receiver amplifiers. RF cavity filters may be used in linear power amplifiers and radio equipment such as cellular base stations, among other things, to, for example, reduce undesired frequencies in an RF signal, or to delay an RF signal by a predetermined amount of time. Radio frequency (RF) filters and multiplexers having filters typically employ a plurality of resonators.