Single layer reflectarray employing circular ring with open-circuited stub as phasing element (original) (raw)
Related papers
2010
A new phasing element for use in a wideband microstrip reflectarray is described. It is formed by a variable length arc attached to a fixed size circular ring. It is shown that the new phasing element offers a double resonance with an increased phasing range that is welcome in the reflectarray phase compensation procedure. The extended phase range enables the use of a thicker substrate to obtain a slower phase slope and thus an increased operational bandwidth of the reflectarrray. In the proposed approach, an increased reflectarray thickness is achieved using a foam layer placed underneath the substrate laminate carrying the phasing elements pattern. The usefulness of the newly proposed phasing element is demonstrated in the design of a 13x13 element reflectarray. Full wave EM simulations carried out with CST Microwave Studio confirm a wideband operation of the designed reflectarray.
2008
The paper reports on the investigations into phasing characteristics of a unit cell of a single-layer microstrip reflectarray including variable size double rings of square or circular shape. It is shown that if the rings are printed on a conventional dielectric substrate, the phasing characteristics of the unit cell exhibit the phase range well in excess of 360deg but with a sharp slope. By printing the double ring elements on a thick composite substrate formed by a thin laminate and thick foam a slower slope and a reduced range but still covering 360deg can be obtained. The use of such a unit cell can lead to a wideband design of a single layer microstrip reflectarray.
A Compact Single Layer Reflectarray Antenna Based on Circular Delay-Lines for X-band Applications
Radioengineering, 2018
This paper presents a compact single layer reflectarray antenna based on a diagonally notched square patch and a pair of circular delay-lines, for X-band applications. The length and width of circular delay-lines are varied and optimized to attain a linear phase range of more than 600º. The effect of incident angle in TE and TM modes at 0º, 15º and 30º is studied, which offers stable angular phase range. The hybrid Finite Element Boundary Integral (FEBI) method is used for simulation of the whole reflectarray system comprising of 27 × 27 elements and being fabricated on a low cost FR-4 laminate. The measured gain of 24.5 dBi with aperture efficiency of 49.5% is achieved at 10 GHz. The proposed design provides the measured 1-dB gain bandwidth of 12.5% and 3-dB gain bandwidth of 34%. The simulated and measured side-lobe-levels and cross polarizations are less than-25 dB and-40 dB, respectively.
Modified Phasing Element for Broadband Reflectarray Antennas
Progress In Electromagnetics Research C, 2017
New phasing element for a wideband microstrip reflectarray is presented. It is formed by a phase-delay line attached to a circular ring loaded with a circular disc microstrip. The structure is enclosed by a circular ring element with a pair of gaps. It is shown that the new phasing element offers a wider bandwidth with an increased phasing range that is useful in reflectarrays phase compensation procedure. Full wave EM simulations are carried out. Good agreement exists between simulation results and measurements by using waveguide simulator method. The mutual coupling effect for a realistic reflectarray configuration with non-identical cells is accounted for by using the perturbation technique.
Double-Layered Circular Microstrip Reflectarray Element With Broad Phase Range
Progress In Electromagnetics Research C, 2014
In this paper, a double-layered microstrip reflectarray element is studied. The unit element consists of a circular patch sandwiched between two substrates and a cross-slotted circular patch placed on the top-most surface. The radii of the two circular patches as well as the cross-slot lengths are varied simultaneously for controlling the phase range and the gradient of the reflection phase angle. Study shows that the sensitivity of the reflection phase angle can be made slower by utilizing substrates with lower dielectric constants. The component performance is studied using a rectangular waveguide and good agreement is found between the simulation and experiment. A wide reflection phase range of 681.82 • with loss magnitude less than −1 dB is achievable in the reflection phase angle. A complete parametric analysis has been conducted to study the reflection characteristics of the proposed reflectarray unit element.
Circular polarized reflectarray antenna
20th Iranian Conference on Electrical Engineering (ICEE2012), 2012
In this paper, aperture coupled dielectric resonator antenna loaded with rotated strip, is used as a CP element for reflect array antenna. Phase variations are obtained by a symmetric change in the length of the stub. The effect of the various parameters of the structure on the slope of the phase curve is studied. Simulations are carried out with Ansoft HFSS software. Linear phase curves with more than 400 degrees phase shifts are achieved in 21 percent frequency bandwidth. Finally axial ratio performance of an array with 256 elements is calculated using the finite integration technique (FIT) in CST MWS software is calculated.
Design and Implementation of a Broadband Single Layer Circularly Polarized Reflectarray Antenna
IEEE Antennas and Wireless Propagation Letters, 2012
The design and implementation of a broadband single-layer circularly polarized reflectarray antenna is presented in this letter. Each element in the proposed reflectarray consists of a circular microstrip patch attached to four variable-length phase delay lines to achieve more than 650 of linear phase for frequencies in the range 9.6-11.2 GHz. Measurement results show 15.5% 3-dB gain bandwidth and 14.6% 3-dB axial-ratio bandwidth.
A Single-Layer Broadband Reflectarray Antenna by Using Quasi-spiral Phase Delay Line
IEEE Antennas and Wireless Propagation Letters, 2015
A novel broadband unit-cell is proposed in this paper. This new cell element consists of three coupled circular rings where four quasi-spiral delay lines are connected to the outer ring to provide the required phase shift. The spiral shape of the delay lines exhibits more than 1000 o of phase swing. The cross polarization level of the presented element is considerably improved compared to previous designs with a similar phasing mechanism. The capability of operating in linearly or circularly polarized incident wave is an important advantage of the proposed cell. In other words, depending on polarization of the feed antenna, the present reflectarray can operate in vertical, horizontal or circular polarization. Finally a moderate size reflectarray, 27×27 cm 2 , is designed and fabricated based on the mentioned element. The measured results showed about 16.5% of 1 dB gain bandwidth. The antenna gain at 8.5 GHz is 26.4 dB which is equivalent to 59.2% efficiency. Also, the measured sidelobe level and cross polarization of this antenna are about-20 dB and-25 dB, respectively.
Evaluation of Phase Responses of Double Ring Elements for Reflectarray by Simulation and Measurement
2012 Fourth International Conference on Computational Intelligence, Communication Systems and Networks, 2012
This paper presents design and performance analysis of three proposed shapes for use as microstrip patch elements for reflectarray antenna. The elements are formed of patches of variable size. The comparison focuses on effect of the elements shapes and boundaries on the performance of reflection phase represented by; range, slope and magnitude. Variation of the responses with frequency is also investigated to examine the frequency response of the proposed elements. Three shapes in the form of double-rings inspired by the Koch fractal are investigated. The elements are of single layer configuration printed on composite substrate of FR4 and foam. The bandwidths of the elements were estimated from the phase responses. The analyses were performed using the CST Microwave Studio software package. Experimental validations are given using measurements by vector network analyzer VNA, and employing the X-band waveguide simulator. The elements showed improved bandwidth.