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A 2.4 GHz industrial, scientific, and medical band on-chip antenna (OCA) is integrated into an on-chip broadband balun in $0.18~\mu \text{m}$ CMOS technology on a die of size 4 mm2. Antenna miniaturization is achieved from the capacitive loading of meandered dipole arms. A back-to-back configuration of the balun on a separate die is characterized with in-band insertion and return loss of better than 0.9 dB and 20 dB, respectively. A commercial low-cost package is used to provide a decoupling effect to the OCA when immersed in tissue, enabling it to maintain stable impedance matching as in the air. A detailed explanation of the decoupling mechanism is provided using field plots and equivalent circuit analysis. The OCA is characterized in air and different tissue phantoms with a gain of −23.8 dBi in air and −25.9 dBi inside skin mimicking gel. The maximum simulated uplink specific absorption rate is obtained as 160 $\mu \text{W}$ /kg for an input power of $25~\mu \text{W}$ to the OCA in the transmitting mode. As the antenna has a small footprint and is analytically estimated to be capable of communicating at a high uplink bit rate of 1 Mb/s over a distance of 5.2 m with a 3 dB link margin, it is most suited as a minimally invasive implantable medical device. [ABSTRACT FROM AUTHOR]

This paper presents two end-fed compact Yagi-Uda-type pattern diversity antennas, which use a coplanar-waveguide (CPW)-fed printed pseudomonopole antenna (PPMA) as the driver element. The balun-less driver PPMA behaves like a folded strip dipole and adds to its compactness. A common mode/differential mode (CM/DM) decomposition of antenna current on PPMA is carried out to show that the CM current distribution is similar to the current distribution of an asymmetrically fed dipole. The designed three-element Yagi-Uda antenna operates in the 2.4-GHz band with F/B ratio of about 23 dB and gain of 7.3 dBi. The compact pattern diversity antennas are realized by using two Yagi-Uda antennas separated by a common reflector. Two diversity antennas are realized using two different arrangements of Yagi-Uda antennas. The separation between the constituent PPMAs is varied to study its effect on the isolation and element embedded efficiency. The better of the two diversity antennas has overall footprint area of 65\; \times \;58\;\textmm^2 and the separation between two radiating elements is only 34 mm or 0.272\;\lambda _o. The simulated and measured port isolation (\vert\text S12\vert) between two diversity branches is about 35 and 27 dB, respectively. The signal envelope correlation is 0.018 and the embedded efficiency is about 93%. [ABSTRACT FROM AUTHOR]

A family of position mutated hierarchical particle swarm optimization algorithms with time varying acceleration coefficients (viz. PM_nHPSO-TVAC, n = 1, 2, 3, 4) is introduced in this paper. The proposed position mutation schemes help the swarm to get out of local optima traps and the hierarchical nature of the swarm prevents premature convergence. One distinct advantage of the proposed algorithms over the existing mutated PSO algorithms is that PM_nHPSO-TVAC do not involve any controlling parameter. Performance of the proposed algorithms is evaluated on standard benchmark functions. Comparative study shows that PM_4HPSO-TVAC performs better than the other PM_nHPSO-TVAC, HPSO-TVAC, comprehensive learning PSO (CLPSO), adaptive-CLPSO (A-CLSPO), PSO with time-varying inertia weight (PSO-TVIW), and constriction factor PSO (CFPSO) for the benchmark functions considered. We apply the proposed algorithm to the synthesis of uniformly excited, unequally dpaced linear array to minimize sidelobe level (SLL) and to control first-null-beamwidth (FNBW) and null locations. Further, we apply the proposed algorithm to the synthesis of unequally spaced sparse planar array to minimize SLL. [ABSTRACT FROM PUBLISHER]