Liquid Crystal Based Dielectric Waveguide Phase Shifters for Phased Arrays at W-Band

Reese, Roland; Polat, Ersin; Tesmer, Henning; Strobl, Jonathan; Schuster, Christian; Nickel, Matthias; Granja, Angel Blanco; Jakoby, Rolf; Maune, Holger

doi:10.1109/access.2019.2939648

Cited by 37 publications

(41 citation statements)

References 17 publications

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“…The measurement of this demonstrator revealed a differential phase shift of 387 • at 25 GHz, with an insertion loss ranging from 3.5 dB to 5.5 dB depending on the tuning state. Here, the maximum FoM achieved is 70 • /dB (see (1)), which is comparable to other similar phase shifter topologies like ridged hollow waveguide [16] or inverted Microstrip lines [17], but cannot compete with hollow waveguide [8] or sub wavelength fiber [18] topology. A more comprehensive comparison with other LC based phase shifters is given in Table 4.…”

Section: Discussionsupporting

confidence: 62%

Ridge Gap Waveguide Based Liquid Crystal Phase Shifter

et al. 2020

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In this paper, the gap waveguide technology is examined for packaging liquid crystal (LC) in tunable microwave devices. For this purpose, a line based passive phase shifter is designed and implemented in a ridge gap waveguide (RGW) topology and filled with LC serving as functional material. The inherent direct current (DC) decoupling property of gap waveguides is used to utilize the waveguide surroundings as biasing electrodes for tuning the LC. The bed of nails structure of the RGW exhibits an E-field suppression of 76 dB in simulation, forming a completely shielded device. The phase shifter shows a maximum figure of merit (FoM) of 70 • /dB from 20 GHz to 30 GHz with a differential phase shift of 387 • at 25 GHz. The insertion loss ranges from 3.5 dB to 5.5 dB depending on the applied biasing voltage of 0 V to 60 V. INDEX TERMS Liquid crystals (LC's), tunable phase shifter, phased array, gap waveguide, bed of nails.

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Section: Discussionsupporting

confidence: 62%

Ridge Gap Waveguide Based Liquid Crystal Phase Shifter

et al. 2020

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“…Finally, a comparison between the proposed phase shifter and other reconfigurable phase shifters in mm-wave frequencies is illustrated in Table I. The proposed reconfigurable phase shifter achieves a better performance in insertion losses and FoM (figure-of-merit) along the operating frequency [13]. The return losses (RL) achieved by our phase shifter has good performance compared with the referenced works except for [26].…”

Section: Experimental Validationmentioning

confidence: 92%

“…Some of the reported tunable phase shifters require a complex setup [5] or a more complicated implementation of the tuning elements in the waveguide [15]. By applying the gap waveguide to the phase shifter design, more options in the location of the gap for the split waveguide is achieved in contrast with the traditional implementation using E-plane split waveguide [13]. In addition, compared with the commercial devices [27], [28], the gap-waveguide phase shifter presents a reduced volume and low cost that allow a cost-effective and easy integration in a full system.…”

Section: Experimental Validationmentioning

confidence: 99%

“…Nevertheless, PIN diodes suffer from high losses in mm-wave regime. Some reconfigurable material such as liquid crystals [13]- [17] or ferroelectrics [18]- [20] are also used to vary the phase shift. These approaches are currently attractive but present some drawbacks such as complex implementation in waveguide and high insertion losses incurred when the frequency increases.…”

Section: Introductionmentioning

confidence: 99%

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Low-Loss Reconfigurable Phase Shifter in Gap-Waveguide Technology for mm-Wave Applications

Palomares‐Caballero

Alex‐Amor

Escobedo

et al. 2020

IEEE Trans. Circuits Syst. II

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In this brief, we present a low-loss mechanically reconfigurable phase shifter implemented in gap-waveguide technology for mm-wave frequencies. The proposed design gives a practical implementation of tuning elements inside the waveguide providing alternatives to the use of the E-plane split waveguide at high frequencies in order to avoid leakage losses. The depicted phase shifter design is based on a H-plane split waveguide. The phase shift is controlled by means of a tuning screw, which exerts pressure on a flexible metallic strip inserted inside the waveguide. The flexible strip bends with different curvature radii and determines the phase shift at the output port. Costeffective manufacturing and simple implementation of the flexible metallic strip are achieved by means of the gap-waveguide design. A prototype has been manufactured for validation purposes. Good impedance matching is achieved from 64 GHz to 75 GHz providing a 15.8% impedance bandwidth. The results show a maximum phase shift of 250 o with a maximum and mean insertion loss (IL) of 3 dB and 1.7 dB, respectively.

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“…Regarding the power losses and radiation efficiency, a better alternative is the use of waveguide antenna arrays. In the recent years some advances have been made in the integration of tunable electronic components with waveguide devices [12]- [15], although there is still margin for improvement. On the other hand, while presenting a longer reconfiguration time than the electronic alternatives, mechanical reconfiguration techniques are specially adequate to achieve high performance and low power losses [16]- [18].…”

Section: Introductionmentioning

confidence: 99%

Mechanically Reconfigurable Linear Phased Array Antenna Based on Single-Block Waveguide Reflective Phase Shifters With Tuning Screws

et al. 2020

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This work presents the design and prototyping of a reconfigurable phased array in Ku band (16 to 18 GHz) implemented in waveguide technology. The design is based on the use of a novel seamless waveguide module integrating four reconfigurable phase shifters to adjust the relative phase shift between the unitary elements of a linear array, which are illuminated uniformly by a corporate waveguide feeding network. The phase shifters are implemented by a 90 ○ hybrid coupler in waveguide technology where two of its ports are loaded with a tunable reactive load, implemented in this proof of concept with a tuning screw. The four phase shifters have been manufactured in a single part using direct metal laser sintering, avoiding the losses related to bad electric contacts and misalignments associated to multipart devices. This also simplifies the assembly of the full phased array, leading to a modular approach with three parts whose design can be addressed separately. The experimental results for the complete array antenna show great performance and demonstrate that the main-lobe of the radiation pattern can be effectively scanned continuously between the angles −25 ○ and 25 ○ , with a high efficiency in the whole design band thanks to the proposed waveguide implementation.

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Liquid Crystal Based Dielectric Waveguide Phase Shifters for Phased Arrays at W-Band

Cited by 37 publications

References 17 publications

Ridge Gap Waveguide Based Liquid Crystal Phase Shifter

Ridge Gap Waveguide Based Liquid Crystal Phase Shifter

Low-Loss Reconfigurable Phase Shifter in Gap-Waveguide Technology for mm-Wave Applications

Mechanically Reconfigurable Linear Phased Array Antenna Based on Single-Block Waveguide Reflective Phase Shifters With Tuning Screws

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