A new high performance phase shifter using Ba/sub x/Sr/sub 1-x/TiO<sub>3</sub> thin films

Acikel, B.; Taylor, T. R.; Hansen, P.; Speck, James S.; York, R.A.

doi:10.1109/lmwc.2002.801129

Cited by 175 publications

(53 citation statements)

References 4 publications

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“…[1][2][3][4][5][6] However, the dielectric behavior of these materials depends very strongly on temperature near the Curie temperature T C . This means that, for conventional ferroelectrics, the dielectric properties of the tunable devices may drift strongly depending on ambient conditions.…”

Section: Introductionmentioning

confidence: 99%

Graded ferroelectric capacitors with robust temperature characteristics

El‐Naggar

Dayal

Goodwin

et al. 2006

Journal of Applied Physics

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Ferroelectric thin films offer the possibility of engineering the dielectric response for tunable components in frequency-agile rf and microwave devices. However, this approach often leads to an undesired temperature sensitivity. Compositionally graded ferroelectric films have been explored as a means of redressing this sensitivity, but experimental observations vary depending on geometry and other details. In this paper, we present a continuum model to calculate the capacitive response of graded ferroelectric films with realistic electrode geometries by accurately accounting for the polarization distribution and long-range electrostatic interactions. We show that graded c-axis poled Ba x Sr 1−x TiO 3 ͑BST͒ parallel plate capacitors are ineffective while graded a-axis poled BST coplanar capacitors with interdigitated electrodes are extremely effective in obtaining high and temperature-stable dielectric properties.

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Section: Introductionmentioning

confidence: 99%

Graded ferroelectric capacitors with robust temperature characteristics

El‐Naggar

Dayal

Goodwin

et al. 2006

Journal of Applied Physics

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“…The advantages of BST include dc voltage tunable high permittivity, high capacitance density (10-100 nF/mm 2 ), bipolar dc bias for tuning the varactor, large capacitance tuning range (>3:1), high power handling capability (>1 W), good temperature stability from 0 C to 110 C in thin films compared to bulk oxides, and quality factor in the frequency range of 1-10 GHz comparable to semiconductor varactor diodes. Applications demonstrated using BST thin film varactors include tunable filters, 8 tunable phase shifters, 9 delay lines, 10 VCO, 11 and reconfigurable antennas. 12 Table I compares the BST thin film varactor technology with semiconductor diode and the RF MEMS capacitor technologies.…”

Section: Current State Of the Art Of Multifunctional Oxide And Mumentioning

confidence: 99%

“…9,[87][88][89][90][91][92] The most popular implementation of phase shifters is using the distributed transmission line phase shifter (DTLPS), where the varactors are typically shunt loading the transmission lines periodically. 9,89 By varying the capacitance, the phase velocity and hence the relative phase shift between the input and output can be accomplished. Typical phase shifters require both low insertion loss and high phase shift.…”

Section: Phase Shifters For Electronic Steering Of Antenna Arraysmentioning

confidence: 99%

“…Significant progress has been made on large area BST thin film process development on sapphire and high resistivity Si. 9,39 While the BST thin film based varactors fabricated on sapphire substrates could be useful for microwave applications, integration of BST thin film on standard CMOS silicon will be attractive for technology insertion into commercial RF/wireless communication circuits. Fabrication of BST thin films on high resistivity Si has been done by many researchers.…”

Section: Substrates and Packaging Considerationsmentioning

confidence: 99%

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Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components

Subramanyam¹,

Cole²,

Sun³

et al. 2013

Journal of Applied Physics

147

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There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated in different multiferroic heterostructures, which show giant voltage control of the ferromagnetic resonance frequency of more than two octaves. This manuscript reviews recent advances in the processing, and application development for the complex oxides and multiferroics, with the focus on voltage tunable RF/microwave components. The over-arching goal of this review is to provide a synopsis of the current state-of the-art of complex oxide and multiferroic thin film materials and devices, identify technical issues and technical challenges that need to be overcome for successful insertion of the technology for both military and commercial applications, and provide mitigation strategies to address these technical challenges. V C 2013 AIP Publishing LLC.

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“…To implement a phase shifter, many circuit topologies exist, e.g. capacitively loaded transmission line [1], reflection-type [2], etc. Among them, all-pass network has been used to realize both digital [3,4] and analog phase shifters [5,6].…”

Section: Introductionmentioning

confidence: 99%

Broadband analog phase shifter based on multi-stage all-pass networks

Chen

2013

IEICE Electron. Express

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All-pass phase shifters using ferroelectric varactors are designed, fabricated, and measured. The design equations for the allpass phase shifter are presented. The fabrication process of the ferroelectric varactors is described. Measurement results of singlestage all-pass phase shifters show that phase shift greater than 85ﾟ can be achieved under 10-V bias. At the frequency where maximum phase shift occurs, the insertion loss is less than 2 dB and the return loss is greater than 12 dB. Simulations based on the measured S parameters of the single-stage phase shifters show that, by cascading four stages of individually biased single-stage phase shifters, maximum phase shift of 180ﾟ can be achieved with a phase error as low as ±3ﾟ between 2.1 GHz and 3.25 GHz, corresponding to a 43% bandwidth.

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A new high performance phase shifter using Ba/sub x/Sr/sub 1-x/TiO₃ thin films

Cited by 175 publications

References 4 publications

Graded ferroelectric capacitors with robust temperature characteristics

Graded ferroelectric capacitors with robust temperature characteristics

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components

Broadband analog phase shifter based on multi-stage all-pass networks

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A new high performance phase shifter using Ba/sub x/Sr/sub 1-x/TiO3 thin films

Cited by 175 publications

References 4 publications

Graded ferroelectric capacitors with robust temperature characteristics

Graded ferroelectric capacitors with robust temperature characteristics

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components

Broadband analog phase shifter based on multi-stage all-pass networks

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Product

Resources

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A new high performance phase shifter using Ba/sub x/Sr/sub 1-x/TiO₃ thin films