Design of small directive antennas for IoT E4 Final Project Prepared by: Habib Mariam Luvuezo Holldry Submitted for: Prof. Alves Thierry July, 2017

Design of small directive antennas for IoT

Outlines Introduction WSN and IoT Antenna theory Practical work Conclusion Knowledge gained Design of small directive antennas for IoT 3

Introduction Design of small directive antennas for IoT Internet of Things (IoT) Internet of Things (IoT) 4

Internet of Things (IoT) Design of small directive antennas for IoT IoT is the term used to describe any kind of applications that are connected and made “things” interact through the internet. SENSORS 5

Wireless Sensor Networks (WSN) Design of small directive antennas for IoT WSN is a group of small devices that are connected to the internet through the gateway It’s called Sensor Nodes These small devices have sensing, data processing and wireless communication capabilities 6

Wireless Sensor Networks (WSN) Design of small directive antennas for IoT At the moment, Small directive antennas are not used in the IoT. o Advantages of using directive antennas in IoT: Create new channels Reduce the interference between the nodes operating at the same frequency 7

Antenna Theory

What is antenna? Antenna is defined as a metallic device for radiating/ receiving radio waves. Design of small directive antennas for IoT Thus, antenna is considered as the transitional structure between free space and a guiding device. 9

Antenna Parameters o The performance of an antenna is defined by a set of parameters: Design of small directive antennas for IoT Radiation pattern Radiation intensity Radiation power density Input impedance Efficiency Gain Bandwidth 10

Half wave dipole antenna It’s formed from a half wavelength long conducting element with a feeder connected in the center. Design of small directive antennas for IoT Dipole antenna structure and radiation pattern Half wave dipole characteristics: Maximum directivity of 2.15 dB Radiation resistance of 73 Ω Linear current with amplitude varies as one half of a sine wave, maximum at the center. It’s the basic unit of Yagi- Uda antenna. 11

Miniaturization Design of small directive antennas for IoT o Advantages of miniaturization: Physical size reduction Higher radiation efficiency Wider bandwidth o Miniaturization techniques: Loading the with high contrast material, high permeability/permittivity Modification of the geometry and shape The use of lumped components Frequency band structure, artificial magnetic conductors and left handed propagating components 12

Antenna Array Design of small directive antennas for IoT Antenna array: A group of identical (conventionally) antennas interconnected and arranged in a regular structure to form an array. It’s built to control the radiation intensity, field strength, directivity, polarization, radiation pattern and the gain depending on the application One of the most successful RF antenna design for directive antennas is Yagi Uda antenna 13

Yagi Uda antenna Design of small directive antennas for IoT o Structure Driven element: half wave dipole antenna Reflector (backward gain) Director (forward gain) 14 Yagi antenna structure and radiation pattern

Design of small directive antennas for IoT Practical Work

Design Requirements Design of small directive antennas for IoT 16

Design Procedures Design of small directive antennas for IoT 1.Design of simple 2 elements half wave directive antenna operating at 2400 MHz 2.Design of small directive antennas operating at 868 and 2400 MHz by applying the meandered lines miniaturization approach. 17

1. Design of simple 2 elements Yagi antenna operating at 2400 MHz. Design of small directive antennas for IoT Outcomes: o SWR= o F/B= 10.3 dB o Gain= 6.54 dBi 18

2. Design of 2 elements small directive antennas Design of small directive antennas for IoT Design Procedures: 19

Design of a small directive antenna operating at 868 MHz [1] Design of small directive antennas for IoT 3D geometry of 868 MHz small directive antenna 20

Design of a small directive antenna operating at 868 MHz [2] Design of small directive antennas for IoT 1.Simulation results 2.Total gain (dBi) 3.SWR 4.Reflection coefficient

Design of a small directive antenna operating at 868 MHz [3] Design of small directive antennas for IoT 1.F/B 2.Impedance 3.Radiation pattern

Design of a small directive antenna operating at 2400 MHz [1] Design of small directive antennas for IoT 3D geometry of 2400 MHz small directive antenna 23

Design of a small directive antenna operating at 2400 MHz [2] Design of small directive antennas for IoT 1.Simulation results 2.Total gain (dBi) 3.SWR 4.Reflection coefficient

Design of a small directive antenna operating at 2400 MHz [3] Design of small directive antennas for IoT 1.F/B 2.Impedance 3.Radiation pattern

Results and Comments Design of small directive antennas for IoT 1.Standing Wave Ratio (SWR)2.Reflection coefficient 26

Results and Comments Design of small directive antennas for IoT 3.Gain (dBi) 4.Front to back ratio (dB) 27

Results and Comments Design of small directive antennas for IoT 5.Radiation efficiency6.Radiation pattern o Radiation pattern of Yagi antenna has: Main lobe ( wide on the x- axis ) Back lobe 2 side lobes. 28

Results and Comments Design of small directive antennas for IoT 7.Comparison of the radiation pattern of simple 2 elements Yagi antenna and the miniaturized design o More efficient o Higher gain o Higher front to back ratio 29

Results and Comments Design of small directive antennas for IoT 8.Comments on the antenna array parameters: The reflector size and spacing have negligible effects on the forward gain but significant effects on the backward gain and input impedance. The size and spacing of the director has a large effect on the forward gain, backward gain and input impedance. The impedance of the driven element is greatly affected by the parasitic elements The Yagi antenna gain is governed by the number of elements in the array and the spacing in between them The most obvious factor that affects the Yagi antenna gain is the number of elements. In one of the trial, another reflector was added, in this case a significant improvement on the gain and directivity of the antenna was provided 30

Design of small directive antennas for IoT Conclusion and Knowledge gained

Knowledge gained Design of small directive antennas for IoT The first and the most important is the antenna theory Two months ago, the antenna field was something obscure, we did not know about it anything except its name. Now and after two months of working in this field between theory and design, we can say that we have some knowledge about antenna and how does it work, so many thanks to you doctor and your efforts are really appreciated. A good knowledge in IoT and WSN which are one of the edge of technology fields A good experience in 4NEC2 as an antenna modeller and optimizer software A good knowledge in the antenna array design and parameters optimization 32

Conclusion Design of small directive antennas for IoT This project demonstrates the possibility to use small directive antennas in IoT technology. The work done was divided into 3 parts: 1.Theoretical study of IoT and WSN 2.Minutely study of antenna theory 3.Applying the theoretical knowledge that was gained through the last two parts in the design of the small directive antenna based on the requirements using 4nec2. 33