Design of Multiplexers for IoT-Based Applications Using Stub-Loaded Coupled-Line Resonators

Area of Science:

• Electrical Engineering
• Electromagnetics
• Microwave Engineering

Background:

• Internet of Things (IoT) systems require efficient multiplexers for managing multiple frequency bands.
• Existing multiplexer designs often face challenges with size, insertion loss, and isolation.
• Microstrip technology offers a compact solution for developing high-performance RF filters.

Purpose of the Study:

• To design and validate microstrip-based diplexer and triplexer filters for IoT applications.
• To achieve high isolation and selectivity across specific frequency bands (2.55 GHz, 3.94 GHz, 5.75 GHz).
• To demonstrate superior performance compared to existing multiplexer designs in terms of size and loss.

Main Methods:

• Design of stub-loaded coupled-line resonators for microstrip multiplexers.
• Incorporation of five transmission poles (TPs) in the diplexer and seven TPs in the triplexer for enhanced selectivity.
• Fabrication on a compact Rogers Duroid 5880 substrate and experimental validation against simulations.

Main Results:

• Achieved low insertion loss: 0.3 dB (diplexer at 2.55 GHz), 0.4 dB (diplexer at 3.94 GHz), 0.3 dB (triplexer at 2.55 GHz), 0.37 dB (triplexer at 3.94 GHz), and 0.2 dB (triplexer at 5.75 GHz).
• Experimental results closely matched simulated performance, confirming design effectiveness.
• Demonstrated high isolation and selectivity crucial for multi-band IoT communication.

Conclusions:

• The proposed microstrip multiplexers, utilizing stub-loaded coupled-line resonators, offer excellent performance for IoT systems.
• The designs provide a compact and efficient solution with low insertion loss and high isolation.
• Validated designs pave the way for improved multi-band communication in IoT devices.