Design of a Low-Noise 2.4/5.5 GHz Dual-Band LNA Based on Microstrip Structure

Area of Science:

• Electrical Engineering
• Radio Frequency (RF) Engineering
• Microwave Engineering

Background:

• Low-noise amplifiers (LNAs) are critical components in modern wireless communication systems.
• Achieving dual-band operation with high performance and compact size presents a significant design challenge.

Purpose of the Study:

• To design and fabricate a single-stage dual-band low-noise amplifier (DB-LNA) operating at 2.4 GHz and 5.5 GHz.
• To achieve excellent noise performance, high gain, and wide bandwidth using a microstrip structure.

Main Methods:

• A purely microstrip dual-band bias circuit (DBBC) using series microstrip lines and radial stubs was employed.
• A series-shunt microstrip matching network was utilized for a compact design.
• The DB-LNA was fabricated using a standard printed circuit board (PCB) process.

Main Results:

• The fabricated DB-LNA achieved gains of 15.6 dB (2.4 GHz) and 12.3 dB (5.5 GHz).
• Excellent input and output return losses were measured at both frequencies.
• Low noise figures (NF) of 1.0 dB (2.4 GHz) and 1.1 dB (5.5 GHz) were recorded, with -3 dB bandwidths exceeding 200 MHz.

Conclusions:

• The proposed DB-LNA demonstrates superior noise performance and bandwidth compared to existing designs.
• The compact microstrip structure and dual-band bias circuit enable efficient dual-band amplification.
• This design offers a promising solution for high-performance wireless communication systems requiring compact form factors.