17-21 GHz Low-Noise Amplifier with Embedded Interference Rejection

Abstract

The ever-growing demand for high performance wireless connectivity has led to the development of fifth-generation (5G) wireless communication standards as well as satellite communication (Satcom). Both 5G wireless communications and Satcom use higher carrier frequencies than traditional standards such as 4G and WiFi. While the higher carrier frequencies allow for larger bandwidths and faster data rates, they come with the cost of high free-space path loss. This high loss necessitates the use of active phased array antennas, which can require hundreds of integrated circuits (ICs) designed in Complimentary Metal-Oxide Semiconductor (CMOS) processes. Furthermore, in a future world with ubiquitous 5G wireless base stations and Satcom users, it is conceivable that Satcom receivers can be jammed by high-power Satcom transmitters and 5G signals. Therefore, Satcom phased arrays must be designed for resilience against these sources of interference while supporting high data rates.

One of the key components in a Satcom receiver is the low-noise amplifier (LNA). It is responsible for amplifying the weak, noisy signal received from the satellite into a signal with sufficiently high signal-to-noise ratio for demodulation. One possible solution for making the phased array resilient to sources of interference is to embed filtering in the LNA.

This thesis presents two LNA designs that employ embedded filtering for resiliency to interference from 5G wireless signals and Satcom transmitters. First, the circuit-level specifications of a 17.7 - 21.2 GHz (K-band) LNA for satellite communication phased array beamformers are derived from the system requirements. Next, the LNA designs are presented. The first LNA is designed to have out-of-band filtering at 24-30 GHz, which corresponds to the bands containing both 5G and Satcom transmitter interferers. The second LNA is designed to have out-of-band filtering at 27-30 GHz, which addresses a different scenario where the Satcom transmitter is the sole source of interference. Both LNAs are implemented in the Global Foundries 130nm 8XP Silicon-Germanium Bipolar CMOS (SiGe BiCMOS) process. A novel transformer feedback notch is introduced that enhances the filtering capabilities of the amplifier. The full electromagnetic simulation of the first LNA shows a peak gain of 28.8 dB, a minimum noise figure of 1.85 dB, and and input 1 dB compression point (IP1dB) greater than -17 dBm between 24 and 30 GHz. The second LNA shows a peak gain of 27.9 dB, a minimum noise figure of 1.78 dB, and an IP1dB greater than -15 dBm between 27 and 30 GHz. Both LNAs meet specifications sufficient for a Satcom receiver at the same time as having resiliency to out-of-band interference sources.