Automotive satellite radio services like SiriusXM® were introduced in North America in the early 2000s. Technically known as satellite digital audio radio service (SDARS), the system uses a band at 2.3 GHz to broadcast multiple audio channels from satellites to terrestrial radios. Like other commercial signals broadcast by satellites, such as GPS and GNSS, the low level SDARS signal can be difficult to receive, depending on receiver sensitivity and the amount of RF interference at the receiver. Especially in today’s heterogeneous wireless environment, it is challenging for SDARS to operate in the presence of nearby large signals, like 4G/LTE and Wi-Fi. Without proper filtering and amplification at the RF front-end, the SDARS signal can go undetected or be disrupted by nearby interferers.
Avago Technologies has developed a miniature LNA-filter RFIC module that addresses the wireless coexistence and car antenna footprint challenges faced by SDARS. The ALM-2203 supports both SDARS and GPS/GNSS applications, integrating three PHEMT LNAs with an FBAR filter in a 5 mm × 5 mm × 0.95 mm package. The highly integrated module reduces BOM cost, PCB area and design time. The front-end module combines 0.83 dB noise figure, enhancing SDARS receiver sensitivity, with high out-of-band input P1dB, enabling SDARS coexistence with cellular, Wi-Fi, Bluetooth and GPS signals. The module, designed to retrofit existing GPS/GNSS LNA-filter systems used in today’s shark-fin type car antennas, is approved by SiriusXM.