Internet of Things (IoT) applications require AQ:1 1 orientation insensitive wireless devices to maintain stable and 2 reliable communication as well as the localization capability 3 using the global positioning system (GPS). For those reasons, 4 antennas providing near-isotropic radiation pattern with wide 5 circular polarization (CP) coverage are high in demand for IoT AQ:2 6 applications. In this work, we derive conditions for 3-D antenna 7 on package (AoP), through a combination of three orthogonal 8 dipoles model and particle swarm optimization (PSO) technique 9 to achieve near-isotropic radiation pattern and wide CP coverage 10 simultaneously. Design guidelines have been provided, and a 11 practical AoP has been designed on a 3-D cube package by 12 following this guideline. A prototype has been fabricated and 13 the measured results demonstrate an isotropy of ∼93% and 14 CP coverage of ∼18%, which matches well with the predicted 15 results from the theoretical analysis as well as the full-wave 16 electromagnetic simulations. 17 Index Terms-Circularly polarized antenna, near-isotropic 18 radiation pattern, orientation insensitive antenna. 19 I. INTRODUCTION 20 I NTERNET of Things (IoT) will bring connectivity to the 21 next level, where billions of smart devices to be designed 22 for making decisions for a large number of applications in an 23 automated fashion. These huge numbers of IoT devices will 24 depend on high speed and uninterrupted wireless communica-25 tion for their smooth functioning. Thus, a new generation of 26 antennas is required which are space-efficient, low cost, and 27 orientation insensitive in terms of stable performance. Low 28 cost and efficient space can be achieved through the antenna-29 on-package (AoP) concept.

A low-cost and additively manufactured 3D Antenna-in-Package (AiP) with quasi-isotropic radiation is proposed for a marine animals monitoring system. The antenna is based on a meandered dipole folded as a split ring resonator (SRR) structure, which can generate simultaneously a pair of orthogonal electric and magnetic dipoles, thus providing a quasi-isotropic radiation pattern. The antenna (integrated with a balun) has been inkjet-printed on a 3D-printed buoyant cone structure, which acts also as the system package to house the electronics and the battery. The antenna designed at 2.4 GHz is electrically small, with a = 0.49, and has a bandwidth of 70 MHz (2.9%). The measured gain deviation of the antenna (maximum to minimum) is near 3 dB in bandwidth, thus qualifying it as a quasi-isotropic antenna. Field tests of the antenna in the active state (integrated with the electronics) confirm a reliable communication range of 240 m in any direction in the azimuthal plane.

Internet of things (IoT) applications require orientation insensitive wireless devices to maintain stable and reliable communication. For those reasons, antennas providing a wide quasi-isotropic and circular polarization (CP) coverage are very attractive. However, achieving a wide quasi-isotropic and CP coverage simultaneously is challenging. In this work, we show that properly designed sloped dipoles on a 3D structure can maximize the CP coverage (theoretically up to 100%) even with equal-phased feed to the dipole elements. We derive the conditions and present the design graphs for the optimum slope angle for the dipole elements on a 3D hexagonal-shaped package to achieve a wide quasi-isotropic and CP coverage simultaneously. Based on the proposed theory, a practical antenna has been designed and fabricated using additive manufacturing. The measured results demonstrate a 7dBisotropy of 92% and a CP coverage of 85%, which matches well with the predicted results from the theoretical analysis and full-wave simulations.

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In this letter, a high aperture efficiency (AP), right hand circularly polarized (RHCP), sequentially rotated hexagonal microstrip antenna array, working at GPS L1 band, is proposed. The proposed antenna design is placed on the hexagonal top of a floating sensor node for ocean and marine monitoring applications. To use the hexagonal area effectively and maximize the AP, CP microstrip antenna elements have been distributed centrosymmetric about the origin on the hexagonal substrate. Typically, the AP is enhanced by using thicker substrates, particularly with air gaps. Here, we show a high AP on a very lowprofile substrate (0.011 for the lowest operating frequency) by properly choosing the distance of the antenna elements from the center of the array. The proposed design, based on H-shaped aperture-coupled circular patches, demonstrates a measured gain of 12.4 dBi and an AP of 101%, which is one of the highest reported AP for one of the lowest profile sequentially rotational array.

Internet of things (IoT) applications require orientation insensitive wireless devices to maintain stable and reliable communication as well as the localization capability using the global positioning system (GPS). For those reasons, antennas providing near-isotropic radiation pattern with wide circular polarization (CP) coverage are high in demand for IoT applications. In this work, we derive conditions for 3D antenna-on-package (AoP), through a combination of three orthogonal dipoles model and particle swarm optimization (PSO) technique to achieve near isotropic radiation pattern and wide CP coverage simultaneously. Design guidelines have been provided, and a practical AoP has been designed on a 3D cube package by following this guideline. A prototype has been fabricated and the measured results demonstrate an isotropy of ~ 93% and CP coverage of ~18%, which matches well with the predicted results from the theoretical analysis as well as the full wave electromagnetic simulations.

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