BAW Filters for 5G Bands

Aigner, Robert; Fattinger, Gernot; Schaefer, Michael; Karnati, Kalyan K.; Rothemund, Ralph; Dumont, F.

doi:10.1109/iedm.2018.8614564

Cited by 92 publications

(35 citation statements)

References 3 publications

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“…Moreover, it should be noted that scaling acoustic filters toward high frequencies is critical but fraught with challenges [12]. For frequencies above 2.5 GHz, BAW filters are needed but come with significantly higher cost compared to SAW filters which are commonly deployed below 2.5 GHz [13].…”

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confidence: 99%

A Passive-Mixer-First Acoustic-Filtering Superheterodyne RF Front-End

Seo

Zhou

2021

IEEE J. Solid-State Circuits

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This article presents an agile passive-mixer-first superheterodyne RF front-end that utilizes a gigahertz acoustic filter as its intermediate-frequency (IF) load-essentially a mixer-first acoustic-filtering RF front-end. The passive mixer frequency-translates a sharp but fixed-frequency acousticfiltering response to a much higher and mixer-clock-defined tunable frequency while preserves input matching, high linearity, and introduces minimal loss. In contrast to low-or zero-IF passive-mixer-first receivers which often use active filters at baseband, using an acoustic filter as the IF load is fraught with fundamental challenges. We introduce ON-chip LC tanks, as an impedance shaper, to suppress the acoustic filter impedance components at harmonic frequencies and an all-passive recombination network at IF to share one acoustic filter among multiple paths. Also, we extend the existing analysis of mixer-first frontends from assuming a load impedance with a low-pass frequency response to having a generic load impedance. Our analysis unveils impedance aliasing in a generic mixer-first front-end, motivating the need for an ON-chip impedance shaper. A front-end prototype using a 65-nm CMOS switched-LC passive mixer followed by an off-the-shelf 1.6-GHz surface-acoustic-wave (SAW) filter is designed. In measurement, the RF front-end operates across 2.5-to-4.5 GHz achieving 5.5-dB noise figure and +29.4-dBm IIP3 at 1× bandwidth offset.

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confidence: 99%

A Passive-Mixer-First Acoustic-Filtering Superheterodyne RF Front-End

Seo

Zhou

2021

IEEE J. Solid-State Circuits

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“…In addition to the spurious modes, the acoustic energy confinement also affects the quality factor of the devices. The energy confinement is more critical in the higher frequency because the acoustic losses, including damping loss of metal, often increase with the square of frequency or even worse [28], [51], [52]. To minimize the damping loss, the vibration of A-modes should be restricted in the cavity of LiNbO 3 between the interdigital electrodes.…”

Section: B Energy Confinement and Propagation Directionmentioning

confidence: 99%

“…SAW devices require narrow interdigital electrodes with sub-200-nm width to scale the resonant frequencies to be over 3.5 GHz, which leads to high loss and poor power handling [25]. FBAW or BAW devices are commonly limited in the radio bands below 6 GHz as the edge effects and spurious modes are more pronounced in the higher frequency [28]. Efforts have been made to scale the FBAW device to be 30 GHz [30].…”

Section: Introductionmentioning

confidence: 99%

10–60-GHz Electromechanical Resonators Using Thin-Film Lithium Niobate

Yang

Gao

et al. 2020

IEEE Trans. Microwave Theory Techn.

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This work presents a new class of microelectromechanical system (MEMS) resonator toward 60 GHz for the fifth-generation (5G) wireless communications. The wide range of the operating frequencies is achieved by resorting to different orders of the antisymmetric Lamb wave modes in a 400-nm-thick Z-cut lithium niobate thin film. The resonance of 55 GHz demonstrated in this work marks the highest operating frequency for piezoelectric electromechanical devices. The fabricated device shows an extracted mechanical Q of 340 and an f × Q product of 1.87 × 10 13 in a footprint of 2 × 10 −3 mm 2. The performance has shown the strong potential of LiNbO 3 antisymmetric mode devices for front-end applications in 5G high-band.

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“…Scaling SAW devices over 3.5 GHz requires a sub-200-nm width for interdigital electrodes, which leads to high loss and poor power handling. For BAW devices, efforts have been made to scale them to the X-band (8)(9)(10)(11)(12) [6], [7]. To this end, AlN thin films are thinned down to be around 175 nm, which introduces very stringent requirements on film quality and thickness uniformity [8].…”

Section: Introductionmentioning

confidence: 99%

X-Band Miniature Filters Using Lithium Niobate Acoustic Resonators and Bandwidth Widening Technique

Yang

Gao

Gong

2021

IEEE Trans. Microwave Theory Techn.

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This work presents a class of micro-electromechanical system (MEMS)-driven radio frequency filters in the X-band. The X-band center frequencies are achieved by resorting to the third-order antisymmetric Lamb wave mode (A3) in a 650-nm-thick Z-cut lithium niobate thin film. A novel bandwidth (BW) widening technique based on using the self-inductance of the top interdigital transducers and bus lines is proposed to overcome the limitations set by the electromechanical coupling (k 2 t) and satisfy the demands in miniaturization and wide BW. Four different designs of the filters are designed and fabricated to show the trade-off among BW, insertions loss (IL), out-of-band rejections, and footprint. Due to the spurious-free and high-Q performance of the A3 lithium niobate resonators, the fabricated A3 lithium niobate filters have demonstrated small in-band ripples and sharp roll-offs. One of these fabricated has demonstrated a 3-dB BW of 190 MHz, an IL of 1.5 dB, and a compact footprint of 0.56 mm 2. Another design is fabricated to demonstrate a 3-dB BW of 170 MHz, an IL of 2.5 dB, an outof-band rejection of 28 dB, and a compact footprint of 1 mm 2 .

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BAW Filters for 5G Bands

Cited by 92 publications

References 3 publications

A Passive-Mixer-First Acoustic-Filtering Superheterodyne RF Front-End

A Passive-Mixer-First Acoustic-Filtering Superheterodyne RF Front-End

10–60-GHz Electromechanical Resonators Using Thin-Film Lithium Niobate

X-Band Miniature Filters Using Lithium Niobate Acoustic Resonators and Bandwidth Widening Technique

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