Meaning
Integrated assembly of electronic components that manages the transmission and reception of high frequency signals. The rf front-end sits between the transceiver and the antenna to filter and amplify the radio waves. It is a primary factor in determining the range and sensitivity of a wireless device.
Signal Path
Route taken by the radio waves through the filtering and switching stages. In a typical rf front-end, the incoming signal passes through a low noise amplifier to boost its strength before it reaches the receiver. Outgoing signals are processed by a power amplifier to reach the levels required for transmission.
Filtering Unit
Passive component removes interference from adjacent frequency bands. The rf front-end utilizes surface acoustic wave or bulk acoustic wave filters to ensure only the desired signals are processed. This selective filtering is necessary to prevent the receiver from being overwhelmed by noise from other radios.
High performance filters also protect the sensitive amplifier stages from damage caused by out of band signals. The placement of these filters is a primary part of the board layout.
Loss Management
Careful matching of impedances minimizes the energy lost as heat. Every connection within the rf front-end is tuned to fifty ohms to maximize power transfer. Designers use smith charts and vector network analyzers to verify the performance of these circuits.
