Electronically reconfigurable reflectarrays with nematic liquid crystals

Moessinger, Alexander; Marin, R.; Mueller, Stefan; Freese, J.; Jakoby, Rolf

doi:10.1049/el:20061541

Cited by 108 publications

(60 citation statements)

References 2 publications

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“…In what it follows, some of these methods are mentioned. One class of these methods are based on using materials with tunable electromagnetic parameters by bias voltage, such as liquid crystal [12][13][14][15][16][17], Barium Strontium Titanate (BST) [18] and ferroelectric materials [18][19][20]. The other class is based on using the electronical elements such as PIN diodes [21,22] [28].…”

Section: Introductionmentioning

confidence: 99%

A Novel Bandwidth Enhancement Technique for X-Band Rf Mems Actuated Reconfigurable Reflectarray

Ra’di¹,

Nikmehr²,

Poorziad³

2011

PIER

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Abstract-In this paper, a wideband microstrip antenna for Xband (8.2 GHz-12.4 GHz) applications is introduced. First, simple patch antennas are studied, and a narrowband reflectarray antenna is designed. The resultant design demonstrates better performance than the previously published narrowband microstrip reflectarray antennas. The important features of the employed elements are simple structure, linear operation, and use of Radio Frequency Micro Electro Mechanical Systems (RF MEMS) switches for programmable pattern control. Next, employing our novel method, the designed narrowband structure is converted to broadband reflectarray antenna that can cover the whole X band. This novel idea is based on introducing several ground plane slots and controlling their electrical lengths by RF MEMS switches. By means of this method, 952 and 587 degree phase swing are achieved for continuous and discrete slot length variations, respectively. Application of this method along with smaller switches results in phase swing improvement of up to 1616 degree. In all structures a RT duroid (5880) substrate is selected to lower the back radiation. The achieved return loss in all cases is less than 0.32 dB. In comparison with the previous publications, our novel bandwidth enhancement technique has more generalization capability and results in single layered broadband reconfigurable microstrip reflectarray antennas with linear phase swing, lower cost, and ease of RF MEMS implementation.

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Section: Introductionmentioning

confidence: 99%

A Novel Bandwidth Enhancement Technique for X-Band Rf Mems Actuated Reconfigurable Reflectarray

Ra’di¹,

Nikmehr²,

Poorziad³

2011

PIER

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“…Electronically tunable microstrip reflectarrays are getting more and more attraction and significance these days and are successfully being applied in electronically scanning and beam-steering antennas [1][2][3]. These reconfigurable reflectarrays possess the advantages of both fixed beam reflectarrays (such as small size, less weight and low cost) and active phased arrays (e.g., beam scanning, adaptive radiation pattern and dynamic phase control).…”

Section: Introductionmentioning

confidence: 99%

Equivalent Electrical Circuit for Designing Mems-Controlled Reflectarray Phase Shifters

Tahir¹,

Aubert²,

Girard³

2010

PIER

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Abstract-This article presents an equivalent electrical circuit for designing Radio-Frequency MEMS-controlled planar phase shifter. This kind of phase shifters has recently been incorporated in reconfigurable reflectarrays. The proposed equivalent circuit depends on the number, the ON/OFF state and the locations of the switches inside the unit cell. Such equivalent circuit is used for determining, with a little computational effort, the two important design parameters i.e., the number and the locations of RF-MEMS switches in the phase shifter cell. These two design parameters then allow a designer to design a phase shifter cell having a linear distribution of a given number of phases over 360 • phase range at a single desired frequency.

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“…In the 300 GHz band, reflector antennas with mechanical mechanisms are used to provide the beam scanning in this type of mission [19]. An alternative for electronic beam scanning in these frequency bands can be reflectarrays based on liquid crystals [20,21]. An steerablebeam reflectarray was demonstrated in [21] at 34 GHz, but the same concept can be used at higher frequencies [22].…”

Section: Introductionmentioning

confidence: 99%

Analysis of dual-reflector antennas with a reflectarray as subreflector

Arrebola

Haro²,

Encinar

2008

IEEE Antennas Propag. Mag.

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In this paper, a modular technique is described for the analysis of dual-reflector antennas using a reflectarray as a subreflector. An antenna configuration based on a sub-reflectarray and a parabolic main reflector provides better bandwidth than a single reflectarray, and has a number of advantages compared with a conventional dual-reflector antenna. Examples include the possibility of beam shaping by adjusting the phase on the sub-reflectarray, and potential capabilities to scan or reconfigure the beam. The modular technique implemented for the antenna analysis combines different methods for the analysis of each part of the antenna. First, the real field generated by the horn is considered as the incident field on each reflectarray element. Second, the reflectarray is analyzed with the same technique as for a single reflectarray, i.e., considering local periodicity and the real angle of incidence of the wave coming from the feed for each periodic cell. Third, the main reflector is analyzed using the Physical Optics (PO) technique, where the current on the reflector surface is calculated by summing the radiation from all the reflectarray elements. Finally, the field is calculated on a rectangular periodic mesh at a projected aperture, and then a time-efficient fast Fourier transform (FFT) algorithm is used to compute the radiation pattern of the antenna. The last step significantly improves the computational efficiency. However, it introduces a phase error, which reduces the accuracy of the radiation patterns for radiation angles far away from the antenna's axis. The phase errors have been evaluated for two integration apertures. It has been demonstrated that accurate patterns are obtained in an angular range of ±6°, which is sufficient for large reflectors. The method of analysis has been validated by comparing the results with simulations obtained from GRASP8. Finally, the theoretical beam-scanning performance of the antenna is analyzed.

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Electronically reconfigurable reflectarrays with nematic liquid crystals

Cited by 108 publications

References 2 publications

A Novel Bandwidth Enhancement Technique for X-Band Rf Mems Actuated Reconfigurable Reflectarray

A Novel Bandwidth Enhancement Technique for X-Band Rf Mems Actuated Reconfigurable Reflectarray

Equivalent Electrical Circuit for Designing Mems-Controlled Reflectarray Phase Shifters

Analysis of dual-reflector antennas with a reflectarray as subreflector

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