S-Band Phase-Locked Loop Frequency Synthesizer for Satellite Communication and Space Applications

This paper presents a fully integrated phase-locked loop (PLL) frequency synthesizer in S-band using a 2-µm InGaAs/GaAs heterojunction bipolar transistor (HBT) technology. To obtain lower both in-band and out-band phase noise, Colpitts voltage-controlled oscillator (VCO) and GaAs HBT emitter coupled logic (ECL) PFD and multi-mode programmable frequency dividers were employed. In addition, in order to improve the harmonics suppression, a bandpass filter with sharp roll-off and very wide stopband was also applied. Finally, a PLL was designed, fabricated and measured for verification. The proposed PLL achieves low phase noise of -95 dBc/Hz @10kHz and -130 dBc/Hz @1MHz with reference spur of -66dBc. Additionally, this PLL demonstrates satisfactory harmonics suppression (-43dBc @2f₀, -41dBc @3f₀, and -59dBc @4f₀, respectively) thanks to the on-chip filter. The designed GaAs based frequency synthesizer could be well applied to satellite communication and space applications.