[paper] Compact Wide-Band Antenna

A. Anand Babu, K. Thenmalar

Design and Evaluation of a Compact Wide-Band Antenna for Wearable Wireless Applications

Tehnički vjesnik 32, 6(2025), 2437-2442

Original scientific paper DOI: 10.17559/TV-20241128002156

ECE, Vivekanandha College of Technology, Tiruchengode, Tamil Nadu, India
EEE, Vivekanandha College of Engineering for Women, Tiruchengode, Tamil Nadu, India

Abstract: This article presents a compact wide-band antenna designed for emerging wireless applications. The antenna utilizes a fiberglass-reinforced (FR4) substrate material with a thickness of 1.6 mm as its base. By varying the length and side edge dimensions of the antenna element, the design achieves a wide operational bandwidth ranging from 3.2 to 3.8 GHz, covering all new radio bands. Experimental optimization of various parameters has been conducted to ensure precise tuning within the desired frequency range. The antenna exhibits a uniform radiation pattern across its operating band, ensuring stable performance. Specific Absorption Rate (SAR) evaluations, conducted as per the Federal Communications Commission (FCC) guidelines, confirm the SAR values remain within the prescribed safety limit of 1.6 W/kg when the antenna is positioned on a human phantom model. The proposed antenna also demonstrates high radiation efficiency and peak gain, making it suitable for wearable applications where compact size and reliable performance are critical. This innovative design addresses the growing demand for wide-band antennas in wireless communication systems, emphasizing safety, efficiency, and adaptability for wearable technologies.

Fig: Electric field distribution over the radiating circle at (a) 3.45 GHz; (b) 3.7 GHz

(c) - (d) fabricated antenna images

[paper] Local Variability Evaluation on Effective Channel Length

Juan Pablo Martinez Brito, Graduate Student Member, IEEE, 

and Sergio Bampi, Senior Member, IEEE

Local Variability Evaluation on Effective Channel Length

Extracted with Shift-and-Ratio Method

IEEE TED, vol. 67, no. 11, pp. 4662-4666, Nov. 2020

doi: 10.1109/TED.2020.3017178

Abstract: In this study, the local variation of the effective channel reduction parameter (ΔL=Lm−Leff) of a MOSFET is extracted by means of the traditional shift-and-ratio (SAR) method. ΔL is then correlated with the threshold voltage difference (ΔVTH) between the device under test (DUT) and the reference device. It is demonstrated that there exists an optimal VG range for extracting reliable values of L through the SAR method. Statistical data analysis shows that for R≈ (Llong/Lshort)≈25, better results are achieved since the value of σ(ΔL) varies typically as the reciprocal 1/√ W. The test structure used in this work is a Kelvin-based 2-D addressable MOSFET matrix implemented in 180-nm bulk CMOS technology. The sample space is of 2304 devices divided into nine subgroups of 256 same size closely placed nMOSFETs.

Fig: (a) Full circuit micrograph (b) MOSFET Matrix structure (c) Zoomed-in view at DUTs 

Acknowledgment: The authors would like to thank and acknowledge the Brazilian public company CEITEC S.A. Semiconductors for the measurement infrastructure, the CAD Support Center (NSCAD) at Federal University of Rio Grande do Sul (UFRGS) for electronic design automation (EDA) support, and Silterra Inc. for the silicon prototyping services.