The Impact of Reduced Conductivity on the Performance of Wire Antennas

Abstract

Low cost methods of antenna production primarily aim to reduce the cost of metalization. This might lead to a reduction in conductivity. A systematic study on the impact of conductivity is presented. The efficiency, gain and bandwidth of cylindrical wire meander line, dipole, and Yagi-Uda antennas were compared for materials with conductivities in the range 10 3 to 10 9 S/m. In this range, the absorption efficiency of both the dipole and meander line changed little, however the conductivity significantly impacts on radiation efficiency and the absorption cross section of the antennas. The extinction cross section of the dipole and meander line antennas (antennas that Thevenin equivalent circuit is applicable) also vary with radiation efficiency. From the point of radiation efficiency, the dipole antenna performance is most robust under decreasing conductivity. Antennas studied in this study were fabricated with brass and graphite. Radiation efficiency of the antennas were measured by improved Wheeler cap (IWC) method. Measurement results showed a reasonable agreement with simulations. We also measured the extinction cross section of the six fabricated prototypes.

Effect of conductivity on subdermal antennas

“…Whether the antennas were in air or in contact with muscle, as the conductivity or skin depth of the antenna material is reduced the resonant frequency is lowered, the S 11 degrades, and the bandwidth is increased, similar to results previously reported for other types of antennas in air in . A minimum conductivity of 10 3 S/m could provide sufficient antennas for some applications.…”

“…Figure shows that as the conductivity or skin depth is reduced the resonant frequency is lowered, the S 11 degrades, and the bandwidth is increased. Increased bandwidth for low conductivity dipoles was also seen in, and lower conductivity limit of 500 S/m for RFID dipole antennas at 915 MHz was predicted in . Notably, the PELCO antenna (1 × 10 5 S/m) has a deeper S 11 than gold nanocomposite (7.9 × 10 5 S/m), mainly due to its greater thickness.…”

Fundamental Limitations for Antenna Radiation Efficiency

“…We reported an analysis of the influence of conductivity on efficiency, gain, cross sections, etc. in [5]. It is important to see how a reduction in conductivity can impact on antenna efficiency and its physical bounds.…”

A Compact Dielectric-Filled Slotted Cavity Mimo Antenna

“…The radiation efficiency, η r , of an antenna impacts on the bandwidth and the gain of the antenna as reported in [11]. Figure 5 compares the radiation efficiency of the proposed antenna to the physical bound from [7]:…”