Further reading on integrating Solar Cells and Antennas

1.0 Poly Silicon Solar Cells as a Groundplane for Patch Type Antennas

1.1 A Quarterwave Metal Plate Solar Antenna

A novel design of a quarter wave shorted trapezoidal metal plate solar antenna using high efficiency polycrystalline silicon solar cells is presented. Using the DC conductive parts of the cell as RF antenna elements as well as choosing the radiating element to be a small base trapezoid, better coupling between the feed and shorting plates is ensured and 40.3% size reduction compared to conventional shorted quarter wave patch is obtained. The trapezoidal radiating element covers merely 2.7% of the total available illumination area of the solar cell leaving its efficiency essentially unaffected. The proposed design strategy has been verified by an instantiation operating at 1.957 GHz and has a wide impedance bandwidth of 15.2% with a gain of 4.5dBi.

Further reading:
S.V. Shynu, M. J. Ammann and B. Norton
A Quarterwave Metal Plate Solar Antenna
Electronics Letters, 2008, 44, (9), 570-571.

1.2 Integration of Microstrip Patch Antenna with Polycrystalline Silicon Solar Cell

The implementation of a polycrystalline silicon solar cell as a microwave groundplane in a low-profile, reduced-footprint microstrip patch antenna design for autonomous communication applications is reported. The effects on the antenna / solar performances due to the integration, different electrical conductivities in the silicon layer and variation in incident light intensity are investigated. The antenna sensitivity to the orientation of the anisotropic solar cell geometry is discussed.

Further reading:
S. V. Shynu, M. J. Roo Ons, P.McEvoy, M. J. Ammann, S. J. Mc Cormack and B. Norton
Integration of Microstrip Patch Antenna with Polycrystalline Silicon Solar Cell
IEEE Transactions Antennas & Propagation, 2009, AP-57, (12), 3969-3972.

1.3 Influence of Solar Heating on the Performance of Integrated Solar Cell Microstrip Patch Antennas

The integration of microstrip patch antennas with photovoltaics has been proposed for applications in autonomous communication systems for building fa├žades. Full integration was achieved using polycrystalline silicon solar cells as both antenna ground plane and direct current power generation in the same device. This paper provides an overview of the proposed photovoltaic antenna designs and characterises the variation of the electromagnetic properties of the device with temperature and solar radiation. Measurements for both copper and solar antennas are reported on three different commercial laminates with contrasting values for thermal coefficient of the dielectric constant.

Further reading:
M.J. Roo Ons, S.V. Shynu, M. Seredynski , M.J. Ammann, S.J. McCormack and B. Norton
Influence of Solar Heating on the Performance of Integrated Solar Cell Microstrip Patch Antenna
Solar Energy 2010, 84, (9), 1619-1627.

2.0 Poly-Silicon Solar Cells as a Reflector for a Dipole

2.1 A Microstrip Printed Dipole Solar Antenna using Polycrystalline Silicon Solar Cells

In many solar antenna designs, the radiating element above the solar cell obstructs the incidence of light and thereby reduces the solar cell efficiency. Therefore a reduced size radiating element is always desirable for the integration. Microstrip printed dipole antennas are thus suitable candidates for the design of solar antennas with polycrystalline silicon solar cells. Here we propose a novel method of solar antenna design using a printed dipole integrated with a new type of balun attached to the solar cell.

Further reading:
Shynu Nair, M. J. Roo Ons, M. J. Ammann, S. McCormack and B. Norton
A Microstrip Printed Dipole Solar Antenna using Polycrystalline Silicon Solar Cells
IEEE International Antennas & Propagation Symposium, 2008, San Diego, CA.

M. J. Roo Ons, Shynu Nair, M. J. Ammann, S. McCormack and B. Norton
Polycrystalline Solar Cell as Reflector for Dipole Antennas
23rd European Photovoltaic Solar Energy Conference, Valencia, Spain

3.0 Amorphous Silicon Solar Cells as a Groundplane for Patch Type Antennas

3.1 Dual Band a-Si:H Solar-Slot Antenna for 2.4/5.2 GHz WLAN Applications

A simple and compact design of solar-slot antenna for dual band 2.4/5.2 GHz wireless local area networks (WLAN) applications is proposed in this paper. The design makes use of amorphous silicon (a-Si:H) solar cells in polyimide substrate with embedded twin strip slot structure to generate dual resonant frequencies. A T-shaped microstripline feed is used to excite the twin slot in the a-Si:H solar cell. The measured impedance bandwidth of the proposed solar antenna are 25.9% (642 MHz) centred at 2.482 GHz and 8.2% (420 MHz) at 5.098 GHz. The measured gain at 2.4 and 5.2 GHz are 3.1dBi and 2.1dBi respectively.

Further reading:
S. V. Shynu, M. J. Roo Ons, M. J. Ammann and B. Norton
Dual Band a-Si:H Solar-Slot Antenna for 2.4/5.2GHz WLAN Applications
Radioengineering, Special Joint Issue of COST IC0603 ASSIST and Small Antenna Working Group of the EurAAP, Vol 18, (4), Part 1, 354-358.

3.2 Reconfigurable Antenna with Elevation and Azimuth Beam Switching

A reconfigurable microstrip antenna is proposed for low cost adaptive beam switching applications. A small patch-slot-ring structure is used as the radiating element where an asymmetrical arrangement of PIN diodes is employed to switch the pattern in four directions. The antenna provides pattern switching of 65o and 45o in its fundamental mode for the elevation and azimuth planes respectively. By maintaining the resonant frequency and beamwidth relatively constant, beam switching is realized using a single feed point.

Further reading:
S.V.Shynu and M. J. Ammann
Reconfigurable Antenna with Elevation and Azimuth Beam Switching
IEEE Antennas & Wireless Propagation Letters, 2010, (9), 367-370.

3.3 Transparent patch antenna on a-Si thin film glass solar module

An optically transparent microstrip patch mounted on the surface of a commercially available solar module is proposed. The patch comprises a thin sheet of clear polyester with a conductive coating. The amorphous silicon solar cells in the module are used as both photovoltaic generator and antenna ground plane. The proposed structure provides a peak gain of 3.96 dBi in the 3.4-3.8 GHz range without significantly compromising the light transmission in the module. A comparison between copper and transparent conductors is made in terms of antenna and solar performance. The proposed technique is considerably simpler that previous integration approaches.

Further reading:
M. J. Roo-Ons, S. V. Shynu, M. J. Ammann, S. J. McCormack and B. Norton
Transparent Patch Antenna on a-Si Thin Film Glass Solar Module
Electronics Letters, 2011, 47, (2), (in press).

3.4 On Bifacial Solar Cell Transparancy at Radio frequencies

The use of bifacial cells as a frequency selective surface is proposed in this paper. The lack of the homogeneous rear side metallization and the periodicity of the finger grid contacts enable the bifacial cell structure to act as a wire-grid polarizer allowing transmission of radio waves of certain frequencies and polarizations. Afull-wave integral-equation based electromagnetic simulator was used to determine the transmission loss of a theoretical bifacial cell with mirrored grid finger contacts and various silicon conductivities over the frequency range 2 to 5 GHz. Keywords: Bifacial, solar cell, design, wire-grid polarizer.

Further reading:
M.J.Roo Ons, S.V. Shynu, M.J. Ammann, S.J. McCormack and B. Norton
On Bifacial Solar Cell Transparency at Radio Frequencies
24rd European Photovoltaic Solar Energy Conference, 2009, Hamburg, Germany.

4.0 Solar Cell as radiating elements

4.1 Emitter-wrap-through Photovoltaic Dipole Antenna with Solar Concentrator

A novel photovoltaic dipole antenna employing a solar concentrator as a reflector is proposed. Four identical emitter-wrap-through rear contact solar cells connected in series as a folded dipole are simultaneously used for power generation and as the antenna radiating element, which is located in the focal line of a parabolic solar concentrator. The parabolic structure acts as solar concentrator for the photovoltaic cells as well as a reflector for the folded dipole antenna. Full wave electromagnetic simulation with supportive experimental work validates this design. The measured fractional impedance bandwidth and gain were 21% and 11.1 dBi respectively. The antenna/solar arrangement provide a power output of 73.7 mW for an irradiance of 1000 Wm-2.

Further reading:
M.J. Roo Ons, S.V. Shynu, M.J. Ammann, S.J. McCormack and B. Norton
Emitter-Wrap-Through Photovoltaic Dipole Antenna with Solar Concentrator
Electronics Letters, 2009, 45 (5), 241-243.

Please note these papers can be accessed at http://arrow.dit.ie/