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Over-the horizon wireless communications within the HF-band is subject to the Faraday effect where the polarization of electromagnetic waves rotates due to the ionization and geomagnetic interactions. This results in further signal loss and fading in addition to the usual multi path propagation fading. In this work, based on the standard Watterson HF channel model, a new HF-MIMO fading channel model is developed that takes into account the radiation patterns of transmit and receive antennas, and then the impact of polarization rotation and antenna polarization mismatch on the HF channel capacity is investigated. The case where the transmit and receive antennas are capable of having multiple different polarization radiation patterns is studied, and an the HF channel capacity resulting from an ideal polarization matching algorithm that can track the polarization rotations is evaluated. Based on the simulations, it is observed that significant improvements can be attained by polarization reconfigurable antennas when used against the Faraday rotation induced polarization variations. © 2016 IEEE.

Over-the horizon wireless communications within the HF-band is subject to the Faraday effect where the polarization of electromagnetic waves rotates due to the ionization and geomagnetic interactions. This results in further signal loss and fading in addition to the usual multi path propagation fading. In this work, based on the standard Watterson HF channel model, a new HF-MIMO fading channel model is developed that takes into account the radiation patterns of transmit and receive antennas, and then the impact of polarization rotation and antenna polarization mismatch on the HF channel capacity is investigated. The case where the transmit and receive antennas are capable of having multiple different polarization radiation patterns is studied, and an the HF channel capacity resulting from an ideal polarization matching algorithm that can track the polarization rotations is evaluated. Based on the simulations, it is observed that significant improvements can be attained by polarization reconfigurable antennas when used against the Faraday rotation induced polarization variations. © 2016 IEEE.

A combined frequency and polarization reconfigurable textile based wearable disc monopole antenna is proposed in this paper. The antenna consists of a disc monopole as the radiator and four PIN diodes for realizing the agility property. By varying the different switching combination of the PIN diodes, frequency reconfigurability is achieved between the GSM and ISM band. Two circular polarization states, right hand circular polarization (RHCP) and left hand circular polarization (LHCP) are also realized in each operating frequency band. The upper band polarization state is controlled by a L shaped stub introduced in the ground plane whereas the lower band polarization agility depends on the length of the parasitic arc placed around the main radiator. The antenna is fabricated and its performance is measured to validate the proposed design.

A combined frequency and polarization reconfigurable textile based wearable disc monopole antenna is proposed in this paper. The antenna consists of a disc monopole as the radiator and four PIN diodes for realizing the agility property. By varying the different switching combination of the PIN diodes, frequency reconfigurability is achieved between the GSM and ISM band. Two circular polarization states, right hand circular polarization (RHCP) and left hand circular polarization (LHCP) are also realized in each operating frequency band. The upper band polarization state is controlled by a L shaped stub introduced in the ground plane whereas the lower band polarization agility depends on the length of the parasitic arc placed around the main radiator. The antenna is fabricated and its performance is measured to validate the proposed design.

A combined frequency and polarization reconfigurable textile based wearable disc monopole antenna is proposed in this paper. The antenna consists of a disc monopole as the radiator and four PIN diodes for realizing the agility property. By varying the different switching combination of the PIN diodes, frequency reconfigurability is achieved between the GSM and ISM band. Two circular polarization states, right hand circular polarization (RHCP) and left hand circular polarization (LHCP) are also realized in each operating frequency band. The upper band polarization state is controlled by a L shaped stub introduced in the ground plane whereas the lower band polarization agility depends on the length of the parasitic arc placed around the main radiator. The antenna is fabricated and its performance is measured to validate the proposed design.

A combined frequency and polarization reconfigurable textile based wearable disc monopole antenna is proposed in this paper. The antenna consists of a disc monopole as the radiator and four PIN diodes for realizing the agility property. By varying the different switching combination of the PIN diodes, frequency reconfigurability is achieved between the GSM and ISM band. Two circular polarization states, right hand circular polarization (RHCP) and left hand circular polarization (LHCP) are also realized in each operating frequency band. The upper band polarization state is controlled by a L shaped stub introduced in the ground plane whereas the lower band polarization agility depends on the length of the parasitic arc placed around the main radiator. The antenna is fabricated and its performance is measured to validate the proposed design.

In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna.

In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna.

In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna.

In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna.

The overarching goal of this project was to exploit the transport properties at colloidal and microfluidic dimensions to controllably alter the high-frequency electromagnetic material properties at the macro level. This was to achieve multifunctionality and reconconfigurability at device-level (antenna) scales through tunability provided by a combination of structural colloidal components and functional microfluidic components; the microfluidic system was used to both reversibly control physical properties through fluidic transport and provide pathways for directed colloidal assembly. A series of multidisciplinary activities have been completed to explore these adaptive properties and integrate them into the design of a demonstration vehicle. This includes a combination of microscopy, numerical simulation, scaling analysis, and image analysis which has been used to evaluate and model the multibody forces acting within the colloidal assemblies and fluidic dispersions. New synthesis procedures were developed to provide nano-scale material systems with high aspect ratio particles and test fixtures were developed for the high frequency electromagnetic characterization of these materials. Multi-scale multi-physics modeling was also examined to provide additional insight into the interconnection of physical phenomena that were associated with multifunctional behavior of the antenna systems.