Date of Award
Open Access Master's Thesis
Master of Science in Electrical Engineering (MS)
Administrative Home Department
Department of Electrical and Computer Engineering
Warren F. Perger
Committee Member 1
Paul L. Bergstrom
Committee Member 2
Day by day technology is changing our lives rapidly. With these radical changes, demands in communication industry are also increasing drastically. To cope up with these demands, 2G, 3G, 4G, LTE (Long Term Evolution) communication systems have been introduced. Modern cellular phone should be capable to operate in wide range of frequency spectrum for their global access to provide end user customers these communication services. Hence mobile antennas should be designed in such a way that they should generate wideband operation. But commercially available standalone mobile antennas aren’t capable to operate in all those communication systems, several antennas are used to get complete communication solution. Different ways have been proposed to obtain wide operation for cellular antennas.
Antenna performance characteristics widely depends on the substrates characteristics and their dimensional specifications. The dielectric constant of the substrate along with the loss tangent greatly influence the antenna performance. Different antenna designs have been proposed with the conventional substrates but these conventional substrate in most cases introduces a cumbersome design specification. Polyimide aerogel with their extreme low dielectric constant and low loss tangent can be used as mobile phone circuit board. Capacitive coupled and inductive shorting monopole antenna can be considered as an RLC circuit that generates multiple resonances which enable wide operation in cellular communications. A simple planar slotted capacitive coupled and inductive shorting monopole antenna along with polyimide aerogel as substrate suitable for ten wideband mobile phone operations is presented. These low dielectric constant polyimide aerogel antennas offer wide bandwidth, higher gain and lower mass as compared to the conventional substrate. An ultra-wide band operation is obtained through slotted capacitive coupling feed and inductive shorting of the radiating plate to the ground plate. Capacitive coupling generates high frequency resonance at 1.84 GHz whereas inductive shorting to the ground plate generates low frequency resonance at 780 MHz with an additional resonance at 1.07 GHz due to the effect of higher resonance at 1.84 GHz. This proposed antenna covers a wide band 695 - 2845 MHz that includes ten LTE (LTE700/2300/2500), WWAN (GSM850/900, DCS1800, and PCS1900), GPS and WLAN bands at a 3:1 Voltage Standing Wave Ratio (VSWR). SAR (Specific Absorption Rate) of this proposed antenna is below the SAR standard is presented at the end with the phantom head model. Due to the low dielectric constant of the polyimide aerogel, gain and radiation efficiency are increased while SAR is significantly below the SAR standard for the entire ultra-wide band.
Rahman, Md Mahfuzur, "SMALL SIZE COUPLING FEED AND INDUCTIVE SHORTING ANTENNA FOR WIDE BANDWIDTH, INCREASED GAIN AND EFFICIENCY WITH LOW SPECIFIC ABSORPTION RATE (SAR) OPERATION", Open Access Master's Thesis, Michigan Technological University, 2016.