Tunable microwave and millimeter-wave band-pass filters

Uher, J.; Hoefer, W.J.R.

doi:10.1109/22.76427

Cited by 160 publications

(62 citation statements)

References 30 publications

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“…With growing number of supported frequency bands, the state of art of front ends not only leads to high cost and volume but also to poor performance due to the insertion loss of many cascaded stages and switches in the signal paths [1]. Thus frequency agility (tunability/reconfigurability) is the expected key feature of cost-efficient front end terminals.…”

Section: Introductionmentioning

confidence: 99%

Wide piezoelectric tuning of ltcc bandpass filters

Alahmad

Mäenner

Matz

et al. 2005

IEEE MTT-S International Microwave Symposium Digest, 2005.

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This work treats design and fabrication issues associated with innovative tunable front-end components which combine two different ceramic technologies, namely multilayer ceramic circuit boards (low temperature cofired ceramics or LTCC) and piezoelectric actuator technology within a single device. The need for such components is particularly arising due to the increasing number of wireless services and associated frequency bands in the range between 0.5 and 2.5 GHz. This has led in the past to the concept of software-defined radio (SDR) which would provide a cost-efficient solution by treating signals digitally and software-controlled up to the highest possible frequencies and as close as possible towards the transmit antenna, while the final analogue section at the antenna comprises only few high-performing and frequencyagile, tunable components. However, as a consequence of demanding component specifications, SDR has not yet found noticeable application in consumer markets despite ongoing search for suitable device concepts and fabrication technologies.Similar to the known micro-electromechanical (MEMS) approaches for tuning and switching, this work presents a modified parallel plate capacitor with high-permittivity dielectric and piezoelectrically movable top electrode as a tuning element. Like in MEMS solutions, there is no tunable dielectric material required for tuning as for example paraelectric material, which would introduce additional losses. The proposed device therefore has the potential for a high quality factor. Contrasting MEMS, piezoelectric actuators exhibit proven reliability and lifetime. Also sticking of contact surfaces can be overcome by the actuator force. The size of the actuator in the order of several millimeters is not impedimental in the present context, since it compares well to the size of planar integrated filters in the frequency range mentioned.The vertical movement of the electrode opens an air gap above the dielectric film which allows for substantial lowering of the effective dielectric constant and capacitance. When applied as a shunt capacitor in a coupled microstrip lines LTCC bandpass filter, the center frequency of the filter is tuned from 1.1 GHz to 2.6 GHz (tunability of 135%) with 200 V control voltage and low insertion loss of value 4 dB (at zero-bias) to 2 dB (at the maximum bias). For a more compact size, one electrode of the piezoelectric element is simultaneously used as the center microstrip line of a filter employing three coupled lines. Its equivalent circuit has been used to explore the change of the capacitor parameters across the entire tuning range. The capacitor varied from 7 pF to 1.35 pF with a quality factor between 60 and 160. The quality factor could be improved by a factor of 7 when the metallization of the piezoelectric actuator, changes from 80 nm to 500 nm.This thesis discusses also the effects of tuning mechanism on the overall quality factor, return loss, insertion loss, and the relative bandwidth at the mid of the band as a function of ...

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Section: Introductionmentioning

confidence: 99%

Wide piezoelectric tuning of ltcc bandpass filters

Alahmad

Mäenner

Matz

et al. 2005

IEEE MTT-S International Microwave Symposium Digest, 2005.

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“…The BPF are used in the radio frequency receivers for image frequency rejection outside the image frequency which results in improved sensitivity. The BPF is realised by waveguide which has many advantages such as high rejection of image frequency, high Q value, low insertion loss, good temperature stability, easy design, easy manufacturing and installation [10]. In the design of direct coupling waveguide BPF the inductive diaphragms, pins or E insert are commonly used as coupling network between levels of waveguide resonant cavity [11,12].…”

Section: Introductionmentioning

confidence: 99%

Design of H-Plane Inductance Diaphragm Waveguide Band-Pass Filter for Millimeter Imaging Frontend

Yang¹,

Li²,

Zhang³

et al. 2014

PIER C

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Abstract-This study presents an equivalent circuit and a design of an H-plane waveguide bandpass filter (BPF) with chamfer. Traditionally, only thin inductive diaphragm with no chamfers considered in the direct-coupled cavity theory, but this will lead to difficulties in the BPF manufacturing. During manufacturing process the chamfer cannot be avoided, and its equivalent circuit and effects on frequency shifting are investigated in this paper. A new design method is proposed in order to compensate the effect of chamfer in the half-wavelength resonator connection between the inductance diaphragm and the waveguide. A modified empirical formula and corresponding procedure are provided for designing such filters. The working center frequency and 3 dB bandwidths (BW) are simulated considering different chamfer radius. The simulated center frequencies are 18 GHz, 26 GHz, 34 GHz and 42 GHz, and BWs are 2.265%, 2.5%, 10%, 15% and 20%. Results show that the modified formula, which conforms better with the simulated results, is superior to the traditional formula. Two H-plane waveguide BPFs are manufactured with center frequency 26 GHz with 2.5% BW and 34 GHz with 2.265% BW. The results of the modified formula are in good agreement with measured ones.

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“…In electronics, various tuning elements such as yttrium iron garnet (YIG) resonators, RF microelectromechanical systems (MEMS), and semiconductor varactor diodes have been used to design continuously tunable RF filters [5]- [13]. So far, the YIG filter has been widely and practically used because it has wideband tuning range capability and good selectivity [5]. However, it has a slow tuning speed on the order of milliseconds.…”

mentioning

confidence: 99%

“…For frequency-agile RF systems, a frequency-tunable RF filter is one of the key RF components and has been extensively developed by means of electronics and photonics technologies. In electronics, various tuning elements such as yttrium iron garnet (YIG) resonators, RF microelectromechanical systems (MEMS), and semiconductor varactor diodes have been used to design continuously tunable RF filters [5]- [13]. So far, the YIG filter has been widely and practically used because it has wideband tuning range capability and good selectivity [5].…”

mentioning

confidence: 99%

Rapidly Tunable Dual-Comb RF Photonic Filter for Ultrabroadband RF Spread Spectrum Applications

Kim

Leaird

Weiner

2016

IEEE Trans. Microwave Theory Techn.

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Abstract-We demonstrate a rapidly frequency-tunable radio frequency (RF) filter using microwave photonics technology for ultrawideband RF spread spectrum applications. A pair of electro-optic frequency combs is arranged as a dispersive tapped delay line in a differential detection configuration to implement a programmable finite impulse response RF filter. Our photonic scheme enables both fast frequency tuning on the order of tens of nanoseconds and wide tuning range (>7.5 GHz) with minimal variation of RF gain and passband shape. The low control voltage (ca. 1 V) and the linear relationship between control voltage and passband frequency facilitate agile frequency tuning for processing of signals with time-varying frequency content, while differential detection increases the photocurrent by a factor of two and suppresses common mode intensity noise. We exploit the rapid tunability of the implemented filter to demonstrate dynamic tracking of frequency-hopped and chirped RF signals. An experiment that performs dynamic filtering of an input chirp signal (3.92-GHz center frequency, up-chirped by >2 GHz within 100 ns) obscured by strong broadband noise achieves ∼11-dB signal-to-noise ratio (SNR) improvement. The SNR obtained is in addition to that available from standard matched filtering or pulse compression processing, suggesting strong potential for enhanced resistance against broadband noise jamming.

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Tunable microwave and millimeter-wave band-pass filters

Cited by 160 publications

References 30 publications

Wide piezoelectric tuning of ltcc bandpass filters

Wide piezoelectric tuning of ltcc bandpass filters

Design of H-Plane Inductance Diaphragm Waveguide Band-Pass Filter for Millimeter Imaging Frontend

Rapidly Tunable Dual-Comb RF Photonic Filter for Ultrabroadband RF Spread Spectrum Applications

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