4.1.4 Single-Band Dual-Input Receiver with Single Antenna

In this scenario, only one RF input and one antenna are used. The challenge is to find suitable matching for the input LNA to serve two frequencies. The antenna must have two resonance frequencies or a wide enough range to cover both.

The following figure illustrates a dual low-band receiver configuration where two RFIN_LB inputs are switched to a single antenna using the internal SPDT (RFIN_LB + RFIN_LB + 1 x ANT).

Figure 4-6. Single-Antenna Dual Low-Band Receiver with Internal SPDT Switching

This approach also works without the SPDT. In this case, consider a performance trade-off between the frequencies.

The following figure illustrates a dual low-band receiver setup where two RFIN_LB inputs are directly connected to a single antenna without switching (RFIN_LB + RFIN_LB + 1 x ANT).

Figure 4-7. Single-Antenna Dual Low-Band Receiver Without SPDT (Direct Connection)