Full-wave analysis of microstrip lines on a highly lossy substrate (original) (raw)

An investigation of millimeter wave reflectarrays for small satellite platforms

Acta Astronautica, 2018

This article reports two contributions related to reflectarray antenna design at millimeter waves (mm-waves). First, a closed form analytical formulation is provided for the prediction of reflection properties of square/rectangular mmwaves reflectarray unit cells based on various quality factors and the theory of waveguide coupled resonators. To ensure a high accuracy at mm-waves, the effects of fringing fields, surface waves, metal conductivity, and metal surface roughness are included in the analysis. This analysis program greatly facilitates the parametric studies of a unit cell's constituting parameters to converge on an optimum design solution. Secondly, the concept of phase quantization is proposed for a cost effective realization of mm-waves reflectarrays. The developed formulation in the first contribution was used to design two 3 bit phase quantized, single layer, 19 wavelength, passive reflectarrays at 60 GHz. The test results are compared with simulations and a very good agreement was observed. These findings are potentially useful for the realization of high gain antennas for mm-wave inter-satellite links in small satellite platforms.

Reflectarray Antennas for Dual Polarization and Broadband Telecom Satellite Applications

IEEE Transactions on Antennas and Propagation, 2015

A reflectarray antenna with improved performance is proposed to operate in dual-polarization and transmit-receive frequencies in Ku-band for broadcast satellite applications. The reflectarray element contains two orthogonal sets of four coplanar parallel dipoles printed on two surfaces, each set combining lateral and broadside coupling. A 40-cm prototype has been designed, manufactured and tested. The lengths of the coupled dipoles in the reflectarray cells have been optimized to produce a collimated beam in dual polarization in the transmit and receive bands. The measured radiation patterns confirm the high performance of the antenna in terms of bandwidth (27%), low losses and low levels of cross polarization. Some preliminary simulations at 11.95 GHz for a 1.2-m antenna with South American coverage are presented to show the potential of the proposed antenna for spaceborne antennas in Ku-band.

Optimum Feeds for Reflectarray Antenna: Synthesis and Design

IEEE Transactions on Antennas and Propagation, 2016

The synthesis and design approach for optimum reflectarray antenna feeds is introduced to maximize the obtained aperture efficiency. Feed antennas' radiation patterns are synthesized to uniformly illuminate reflectarray apertures for both center and offset feeding configurations using an inverse problem approach. Moreover, circular horn antennas with coaxial cavities are designed, fabricated and measured to realize the required radiation characteristics covering the satellite communication band X-Ku (10.7-12.7 GHz). Theoretical analysis of the proposed optimum radiation pattern and realization designs are presented in comparison to a conventional conical horn feed showing a potential enhancement of the aperture efficiency. Furthermore, full-wave analysis is used to compute the radiation patterns, frequency responses of the aperture efficiency and beam squints for the proposed realization feed antennas.

Analysis and design of passive and active microstrip reflectarrays

International Journal of Rf and Microwave Computer-aided Engineering, 2003

The design of reflectarrays is a complex and time-consuming process that very often relies on a trial-and-error approach. In this article, a simplified analysis based on a commercial simulator is proposed. This method, valid for both passive and active antennas, uses a simulator to characterize the single radiating cell and evaluates the contribution of the finite ground plane using physical optics approximation. The proposed design technique has been validated by comparing the simulated response of the single element with the experimentally retrieved phase of the active and passive cell. As a proof of the design concept's feasibility, two small reflectarrays, active and passive, have been prototyped and tested. The measured radiation patterns are presented and discussed.

Analysis and Design of an X-Band Reflectarray Antenna for Remote Sensing Satellite System

Sensors, 2022

This paper presents the analysis and design of an X-band reflectarray. The proposed antenna can be used for a medium Earth orbit (MEO) remote sensing satellite system in the 8.5 GHz band. To obtain a nearly constant response along the coverage area of this satellite system, the proposed antenna was designed with a flat-top radiation pattern with a beam width of around 29° for the required MEO system. In addition, broadside pencil beam and tilted pencil beam reflectarrays were also investigated. The feeding element of the proposed reflectarray antennas is a Yagi–Uda array. The amplitude and phase distribution of the fields due to the feeding element on the aperture of the reflectarray antenna are obtained directly by numerical simulation without introducing any approximation. The required phase distribution along the aperture of the reflectarray to obtain the required flat-top radiation pattern is obtained using the genetic algorithm (GA) optimization method. The reflecting elements ...

Investigation into Bandwidth Limitations of Microstrip Reflectarrays

2008

The paper describes theoretical investigations into the bandwidth limitations of a microstrip reflectarray which uses variable size antenna elements for its phasing. Three main factors limiting the bandwidth are considered. The first one is related to the phase compensation that is required to convert a spherical wavefront launched by the feed into a planar wavefront. The second one is linked to the limited phase range of typical microstrip antenna elements. The third one is related to the match between the required phase as a function of frequency and the fixed size elements' phase characteristics. The three factors are responsible for the reflectarray phasing errors that reduce its gain as the frequency departs from the centre frequency. It is shown that the first factor puts an upper limit to the reflectarray operational bandwidth, while the second one has a less profound impact. The third factor is influenced by choice of the element's shape. It is shown that circular and square patches offer better match than printed dipoles to the required phase slopes.

Reflectarray antennas for space applications

2012 IEEE International Conference on Ultra-Wideband, 2012

In this paper, the advantages and recent developments of reflectarray antennas for space applications are reviewed. Basic requirements for space antennas, and the limitations and challenges of conventional designs are discussed. Various advantages of reflectarray antennas over reflectors and phased array antennas are reviewed and it is shown that reflectarray antennas can be a suitable low-cost choice for the new generation of space antennas.