Elsevier

Solar Energy

Volume 73, Issue 6, December 2002, Pages 395-401
Solar Energy

Solar energy collection by antennas

https://doi.org/10.1016/S0038-092X(03)00033-1Get rights and content

Abstract

The idea of collecting solar electromagnetic radiation with antenna-rectifier (rectenna) structures was proposed three decades ago but has not yet been achieved. The idea has been promoted as having potential to achieve efficiency approaching 100% but thermodynamic considerations imply a lower limit of 85.4% for a non-frequency-selective rectenna and 86.8% for one with infinite selectivity, assuming maximal concentration in each case. This paper reviews the history and technical context of solar rectennas and discusses the major issues: thermodynamic efficiency limits, rectifier operation at optical frequencies, harmonics production and electrical noise.

Section snippets

INTRODUCTION

Solar cells, with the exception of their anti-reflection coatings, are quantum devices, only able to be understood and designed by application of quantum physics. However, the wave nature of light is routinely exploited at longer wavelengths in radio and microwave frequency bands. Photon energies are low at radio frequencies and a large number is required to give some particular power density. We tend to use wave models in that regime. At short wavelengths fewer photons are required for the

HISTORY OF SOLAR RECTENNAS

Bailey proposed the idea of collecting solar energy with devices based on the wave nature of light in 1972 (Bailey, 1972, Bailey et al., 1975). He suggested artificial pyramid or cone structures analogous to those found in nature and similar to dielectric rod antennas. His paper describes pairs of the pyramids as modified dipole antennas, each pair electrically connected to a diode (half wave rectifier), low-pass filter and load. The antenna elements needed to be several wavelengths long to

RELATED TECHNOLOGIES

A solar rectenna is similar to a simple radio telescope or radiometer (Burke and Graham-Smith, 1997) except that the radio telescope needs to measure the radiative power received through the antenna, often with a square-law detector which produces an output voltage proportional to the input power, while the rectenna needs to convert that power to useful work. There are also other technologies of relevance.

Filtering

Two filters are usually employed in rectennas (McSpadden et al., 1998, Nahas, 1975). An input filter between the antenna and the rectifier must (a) form an impedance match between the antenna and the subsequent circuitry, (b) ensure a continuous current path for power flow from the antenna despite the intermittent nature of the rectifier current, and (c) prevent the reradiation by the antenna of harmonic energy produced by the non-linear load presented by the rectifier (Brown, 1970). It was

EFFICIENCY LIMITS

Bailey (1972) suggested that 100% solar energy conversion efficiency may be possible but he also claimed the same upper limit for photovoltaic converters in general. There was at that time considerable confusion in the literature about whether the Carnot efficiency limit should apply to solar energy conversion (Bailey, 1980). Today, it is not questioned that it does and, indeed, more restrictive limits apply for any conceivable converter structure. Kraus (1988) also claimed the possibility of

Beam steering

It is common at microwave and millimeter wave frequencies to spatially steer the beam of a phased array antenna without any physical movement by controlling the phase of the signal from each element in the array. This suggests the future possibility of a concentrating solar energy collector with electronic pointing without moving parts.

Frequency up-conversion

The benefits available from up-conversion of sub-bandgap light passing though a bifacial solar cell have been outlined by Trupke et al. (Trupke et al., 2002).

CONClUSIONS

We have reviewed the history and principles of solar antennas and described their technological context. The thermodynamic limit on its performance was explained and quantified as 85.4% for concentrated solar input without frequency selectivity and 86.8% with selectivity. It remains an open question whether an ultimate limit exists closer to 93.3% but such considerations must account for all sources and consequences of electrical noise.

Acknowledgements

The Special Research Centre for Third Generation Photovoltaics is supported by the Australian Research Council’s Special Research Centres scheme. MAG acknowledges the support of a Federation Fellowship and RC is grateful to R. Gough and G. James (CSIRO) and N. Harder and G. Conibeer (UNSW) and H. Linke (U. Oregon) for helpful discussions and to J. Hansen for preparing the figures.

References (50)

  • P. Reimann

    Brownian motors: noisy transport far from equilibrium

    Physics Reports

    (2002)
  • A. Ambrózy

    Electronic Noise

    (1982)
  • Bailey R. L. (1972) A proposed new concept for a solar-energy converter. Journal of Engineering for Power April,...
  • R.L. Bailey

    Solar-electrics

  • Bailey R. L., Callahan P. S. and Zahn M. (1975) University of Florida, Engineering and Industrial Experiment Station....
  • C. Balanis

    Antenna Theory. Analysis and Design

    (1997)
  • V.I. Belinicher et al.

    The photogalvanic effect in media lacking a center of symmetry

    Sov. Phys. Usp.

    (1980)
  • Berland B., Simpson L., Nuebel G., Collins T. and Lanning B. (2001) Optical rectenna for direct conversion of sunlight...
  • W.C. Brown

    The receiving antenna and microwave power rectification

    J Microwave Power

    (1970)
  • W.C. Brown

    The history of power transmission by radio waves

    IEEE Trans Microwave Theory Tech

    (1984)
  • B.F. Burke et al.

    An Introduction to Radio Astronomy

    (1997)
  • Christodoulou C. G. and Wahid P. F. (2001) Fundamentals of Antennas: Concepts and Applications, Tutorial Tests in...
  • Corkish R. and Green M. A. (2002) PV in Europe, WIP, Munich, Rome, 7–11 October (in...
  • Crowley R. J. (2000) Optical antenna array for harmonic generation, mixing and signal amplification. USA Patent no....
  • A. de Vos

    Endoreversible Thermodynamics of Solar Energy Conversion

    (1992)
  • G.M. Elchinger et al.

    Mechanism of detection of radiation in a high-speed metal–metal oxide–metal junction in the visible region and at longer wavelengths

    J Appl Phys

    (1976)
  • R.S. Elliott

    Beamwidth and directivity of large scanning arrays, Part 1

    Microwave J

    (1963)
  • C. Fumeaux et al.

    Lithographic antennas at visible frequencies

    Opt Lett

    (1999)
  • Goswami D. Y. (2001) In Book of Abstracts, Solar World Congress, 25–30 November, Saman, W. (Ed), Australian and New...
  • F. Graham-Smith et al.

    Optics and Photonics: An Introduction

    (2000)
  • Green R. J. (2002) Optical Antenna,...
  • Hirshman W. P. (2001) Beam me down, Scotty. Will space solar power energize the earth? Photon International October,...
  • A.A. Konovaltsev et al.

    Developing wireless energy transfer systems using microwave beams: applications and prospects

    Telecomm Radio Engineer

    (2001)
  • J.D. Kraus

    Antennas

    (1988)
  • R. Landauer

    Solid-state shot noise

    Phys Rev B Condens Matt

    (1993)
  • Cited by (112)

    • Effect of insulator thickness on the electronic transport through CNT-HfO<inf>2</inf>-Au junction for optical rectenna applications

      2021, Surfaces and Interfaces
      Citation Excerpt :

      Optical rectenna has received a lot of interest in recent years as a potential candidate for solar energy harvesting. Contrary to conventional semiconductor-based solar cells, rectenna devices convert the electromagnetic radiation into direct current through rectification using the wave nature of the light [1]. The latter reduces the material dependent limits (e.g., the band gap) for efficient solar conversion [2,3].

    • Nanotools and devices in solar power energy

      2021, Nano Tools and Devices for Enhanced Renewable Energy
    • Nanomaterials for Alternative Energy

      2020, Encyclopedia of Renewable and Sustainable Materials: Volume 1-5
    • Design and optimization of slot nano-antennas for ambient thermal energy harvesting

      2017, Optik
      Citation Excerpt :

      Optical rectenna is an alternative to photovoltaic cells, which is a combination of a rectifier and an antenna. Since then much research has been done to extend the concept of rectennas to the infrared region for solar power conversion [2,4–9]. Recent developments in the fabrication technologies like atomic layer deposition and electron beam lithography permit the fabrication of nanometric devices [10].

    View all citing articles on Scopus
    1

    ISES member.

    View full text