In a multiband receiver several LNAs are connected to a single mixer in order to save chip area. Due to the limitation of broadband RF performance of the components, the receiver is typically structured with several receive band groups, e.g. low band for the RF bands or frequencies from 700 to 1000 MHz and high band for the RF bands or frequencies from 1700 to 2700 MHz. If at a given time only one band with one carrier is active, all mixer outputs can be combined to one baseband signal path.
Some receiver architectures are capable of simultaneously receiving two carriers from a single or multiple RF bands. These receiver architectures typically have a switch to connect any LNA to any mixer, wherein the mixers are required to be broadband enough for both low band and high band operation, and two parallel baseband signal paths are required to generate two parallel baseband signals for each carrier.
Typically a switch is implemented in the RF path between the LNAs and the mixers to connect the RF signal to the appropriate baseband signal path. Nevertheless, a huge drawback of switches in the RF path is that the linearity requirements are degraded by additional elements. As a result, the current consumption increases to compensate for additional elements.