On the Design Techniques of High Gain Packaged Printed Circuit Board (PCB) Based Antennas for Sensing and Internet of Things (IoT) Millimeter Wave Applications: Challenges and Analysis

Advanced wireless integrated systems are highly based on Printed Circuit Board (PCB) technology. Thus, antennas should be designed based on the same technology for full and straightforward integration with these systems. On the other hand, antennas with waveguides and metallic feeds are very bulky and hard to integrate with PCB-based solutions, as they require complex transitions that increase the system cost and losses. Therefore, we shed the light and review thoroughly the challenges and the main strategies and techniques used to design low-cost, high-gain PCB-based antenna solutions for sensing and Internet of Things (IoT) millimeter-Wave (mm-Wave) applications. Several crucial techniques to counter the design impairments of PCB antennas at mm-Wave frequencies are discussed, this includes: (1) The utilization of diffracted fields to increase the main radiating element gain, and reduce the feeding network size. (2) The utilization of Microstrip Line (MSL) radiation losses to implement high gain radiating antenna elements. (3) The utilization of high characteristic impedance lines to feed antenna array elements, and reduce drastically the radiation effects of the feeding network. (4) The utilization of superstrates and polarizers to enlarge the elements spacing in an array configuration, and enhance the gain and side-lobe level performance. An elaborate design and analysis example of a packaged printed feed with symmetric radiation characteristics is detailed out, capitalizing on the advantages of such feed as a replacement for horn antennas and open-ended waveguide feeds for lenses and reflectors.