Design of Miniature Low-Cost Antennas for Compact Low-Data-Rate IoT Terminals

Internet of Things (IoT) is a modern breakthrough technology driving the creation of a hyper-connected, intelligent world, where ubiquitous IoT devices gather and exchange data for monitoring, tracking, and control purposes. It is already being deployed across diverse sectors, such as logistics, agriculture, and healthcare. At its core, IoT enables wireless devices to autonomously communicate over the Internet. Generally, an IoT node integrates an antenna, a radio transceiver, sensors/actuators, and an energy source. Among these components, the antenna remains a major obstacle in developing compact solutions, as its miniaturization significantly degrades its radiation efficiency and bandwidth. Since most IoT devices use low microwave frequencies (≤ 3GHz), where link and energy budgets are more favorable, their antennas are often pushed into the electrically small regime, further complicating impedance matching. The aim of this thesis is to introduce a new design methodology that provides low-cost Electrically Small Antenna (ESA) solutions suitable for integration into commercial 2.4GHz IoT devices. Accordingly, two novel prototypes are designed, experimentally verified, and compared with the state-of-the-art. The first prototype is a novel 2.47GHz linearly polarized ESA based on a planar loop, offering superior performance within a low-cost Printed Circuit Board (PCB) fabrication framework. A notable technical contribution is the design of a novel dual-excitation mechanism that overcomes the size-versus-pattern limitation of conventional loops. This innovation ensures a stable omnidirectional pattern while the antenna's electrical size is adjusted to facilitate impedance matching. Its feasibility in real-world applications is demonstrated through the development of an active ESA oscillator. The second prototype is a novel 2.49GHz low-cost PCB Circularly Polarized (CP) ESA designed using a new arrangement of loop and dipole elements. Unlike state-of-the-art designs, this antenna achieves a compact size and a competitive usable bandwidth while maintaining omnidirectionality within a simple, low-cost PCB platform. Furthermore, its superior versatility is demonstrated by the ease with which its operating frequency can be tuned. The antenna is employed to validate a novel modeling approach that uses resonant RLC circuits to predict its resonant frequency (fo) and quality factor (Qo), thereby aiding the design process and reducing reliance on time-consuming electromagnetic simulations.

Department dc:contributor.department

Electrical and Computer Engineering

Year dc:date.issued

2026

Author dc:creator

• Abdallah, Mahmoud

Advisors dc:contributor.supervisor

• Antar, Yahia
• Freundorfer, Alois

• Electrically Small Antennas
• Internet of Things
• Loop Antennas
• Dipole Antennas
• Omnidirectional Antennas
• Theory of Characteristic Modes

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1974/36043

OAI identifier oai:identifier

oai:queensu.scholaris.ca:1974/36043