Tiger
Junior Member
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Posts: 10
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hi, all I have met a problem when measuring a ssb-mixer: I have to feed four signals(9GHz) with phase relationship (LOinIP,LOinIN,LOinQP, LOinQN ) for mixer(IC), and to ensure the relationship of the signals does not change when arriving at the pads of IC (the IC`s pads are connected by bondwires to PCB`s pads, and then to the SMA connectors through microstrip). By using 90 & 180 degree Hybrids, we can generate the 4 signals from one signal source. Then, we use cables of good phase stability to transmit the four signals to the PCB`s SMA connectors. However, we find the phase relationship of the hybrids`output are sensitive to their loads; by this I mean, if the load is exact 50om, the phase is 90 or 180 degree, while if the load is not 50om, the phase is not 90 or 180 degree either..Here comes my problem: from the SMA connector to the IC, the impedance is not exact 50 om, so the relationship of signals arriving at the IC`s pads is not what I want either.. I`d like to know your suggestions, and how you feed 4 RF signals with phase relationship to your IC. Many thanks!
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