Influence of varying particle sizes on microwave absorbing properties of U-type hexaferrites and development of broadband microwave absorber

Sandeep Kumar,Ratnamala Chatterjee,Narendra Nath Ghosh

doi:10.1063/9.0000056

Abstract

The present study investigates the influence of particle size variation on the microwave (MW) absorbing properties of (Ba0.7Bi0.3)4Co2Fe34.8Zn1.2O60 U-type hexaferrites. The hexaferrite powders of varying particle sizes were prepared through heating at a constant optimized temperature for different holding time (4, 6, 8 and 10 h) using a novel “one-pot” chemical route. With an increase of the holding time (4 to 10 h), the average particle size is found to increase monotonically (∼65 to ∼170 nm). The hexaferrite sample prepared at a holding time of 8 h exhibits an excellent reflection loss (RL) of ‒44.2 dB (99.99% MW absorption) at 11.6 GHz frequency. In addition, a broadband MW absorber has been developed through an ingenious blending of equal amounts of all four hexaferrite powders. The mixed U-type hexaferrite displays an excellent bandwidth of ∼8.4 GHz for 90% or more MW absorption. The reflection losses (S11) are also measured experimentally through one port short-circuited transmission line method using vector network analyzer (VNA). The strong and broadband absorption results suggest that the prepared U-type samples can be utilized in the high-performance MW absorbing applications.

Highlights

In recent years, a rapid rise in the number of wireless and communication industries operating in the GHz frequency range has been the primary source of harmful electromagnetic (EM) pollution.1–3 The ever increasing problem of EM pollution not just degrades the performance of an electronic device and produces harmful effects on the human health.4–6 The microwave (MW) absorbing materials have attracted tremendous attention of the research community for curbing the problems of EM pollution in the GHz frequency range.7–9 the MW absorber is an essential component of a stealthy defense system for suppressing radar detection of the military weapons
The results suggest that MW absorption in the prepared samples can be effectively controlled through the variation of average particle size
U-type hexaferrite samples of varying particle sizes were prepared through a simple “one-pot” chemical method by changing the holding time from 4 to 10 h

Summary

Introduction

A rapid rise in the number of wireless and communication industries operating in the GHz frequency range has been the primary source of harmful electromagnetic (EM) pollution.1–3 The ever increasing problem of EM pollution not just degrades the performance of an electronic device (through EM interference) and produces harmful effects on the human health.4–6 The microwave (MW) absorbing materials have attracted tremendous attention of the research community for curbing the problems of EM pollution in the GHz frequency range.7–9 the MW absorber is an essential component of a stealthy defense system for suppressing radar detection of the military weapons. The hexaferrite powders of varying particle sizes were prepared through heating at a constant optimized temperature for different holding time (4, 6, 8 and 10 h) using a novel “one-pot” chemical route. The hexaferrite sample prepared at a holding time of 8 h exhibits an excellent reflection loss (RL) of −44.2 dB (99.99% MW absorption) at 11.6 GHz frequency.

Results

Conclusion