Directional coupler for use in vco unequal power splitting

Abstract

A transceiver is provided that includes a TX path mixer that up converts, a RX path mixer that down converts, and a local oscillator that provides a mixing frequency for the TX and RX mixers. The transceiver further provides a directional coupler having an input path coupled to the input of a UHF VCO for dividing power to a TX path and a RX path in the directional coupler. A mixer is provided to mix the input / output frequencies from the RX IF / TX IF. The operating frequency range of the directional coupler is greater than the output frequency of the UHF VCO. The directional coupler splits the UHF VCO unequal power at different ports of the directional coupler to redistribute the power in different ports, thus preventing the TX signal from being reflected back to the RX signal. The invention further provides the additional isolation required by the TX local oscillator chain by preventing reverse power feed into the RX local oscillator. The invention additionally provides for a reduced component count thereby providing savings in cost, complexity, size and power consumption.

Description

technical field [0001] The present invention relates generally to wireless communication systems and, more particularly, to directional couplers for use in the field of radio frequency (RF) combiners, such as RF combiners for cellular mobile communication devices. Background technique [0002] In a radio using the superheterodyne principle, all signal frequencies are usually converted to a fixed lower frequency before detection. This fixed frequency is called the intermediate frequency, or IF. A superheterodyne receiver uses the input signal to heterodyne the frequency from a local oscillator (in the receiver). That is, they generate new frequencies by mixing two or more signals in a nonlinear device. A superheterodyne receiver converts an arbitrarily selected input frequency into a common intermediate frequency signal by heterodyning, where amplification and selection (filtering) are provided. [0003] In the mobile terminal's receiver, the local oscillator signal is mix...

AI Technical Summary

Problems solved by technology

These conventional methods have their own advantages and disadvantages, but a common feature is that the power allocated to the RX and TX mixers is equal

Furthermore, these conventional techniques for VCO power distribution require a considerable number of components, including an additional amplifier acting as a buffer in the upconversion path to provide a high degree of isolation from upconversion to downconversion, which results in large The current demand and power dissipation of the

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