This example illustrates a typical RF application where antenna protection against ESD events are needed. Although the topology and recommendations here are for a GPS system, the same principle can be applied for any RF antenna protection for wireless applications such as WiFi, LTE, and Bluetooth. This topology shows a typical GPS transceiver along with the RF front end components necessary for gain and filtering. Traditionally, RF designers had serious doubts on using ESD diodes for protecting ESD events on antenna lines due to the inherent high capacitance of older ESD diodes. For RF and high speed lines running over 1 GHz, a ESD diode must be inherently low in line capacitance and also linear over frequency to avoid harmonic and intermodulation distortion. Typically, choosing a line capacitance less than 1 pF will be appropriate for most wireless applications. However, linearity measurements are needed to understand the harmonic behavior of the low capacitance ESD diode and how it will impact the overall performance of the RF system. Infineon has test reports and application notes on their ESD diodes that discuss distortion in more detail.