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Integrated Inductors for RF Transmitters in CMOS/MEMS Smart Microsensor Systems

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ABSTRACT

This paper presents the integration of an inductor by complementary metal-oxide-semiconductor (CMOS) compatible processes for integrated smart microsensor systems that have been developed to monitor the motion and vital signs of humans in various environments. Integration of radio frequency transmitter (RF) technology with complementary metal-oxide-semiconductor/micro electro mechanical systems (CMOS/MEMS) microsensors is required to realize the wireless smart microsensors system. The essential RF components such as a voltage controlled RF-CMOS oscillator (VCO), spiral inductors for an LC resonator and an integrated antenna have been fabricated and evaluated experimentally. The fabricated RF transmitter and integrated antenna were packaged with subminiature series A (SMA) connectors, respectively. For the impedance (50 Ω) matching, a bonding wire type inductor was developed. In this paper, the design and fabrication of the bonding wire inductor for impedance matching is described. Integrated techniques for the RF transmitter by CMOS compatible processes have been successfully developed. After matching by inserting the bonding wire inductor between the on-chip integrated antenna and the VCO output, the measured emission power at distance of 5 m from RF transmitter was -37 dBm (0.2 μW).

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Measured return loss characteristics (S11) of a fabricated antenna on silicon
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f9-sensors-07-01387: Measured return loss characteristics (S11) of a fabricated antenna on silicon

Mentions: The output impedance of CMOS VCO has been well matched to 50Ω by inserting a passive matching element (series L, 27 nH). After the matching, the output power of the CMOS VCO became 1.09 dBm (=1.28 mW) at the same supply power. The power efficiency has become 50 % higher as compared to that before the matching. Although the matching was performed by a discrete component in this experiment, it is possible to be integrated on the same chip by extracting the proper value of the parameter from the experiment. Figure 9 shows the measured return loss characteristics before and after the impedance matching of the on-chip antenna fabricated on silicon. The center frequency was moved from 600-MHz to 300-MHz as a result of impedance matching. Also, the voltage standing wave ratio (VSWR) is improved by the matching procedure. The measured bandwidth with a VSWR better than 2.0 was approximately 247-to 351-MHz. This corresponds to the measured result of Figure 9.


Integrated Inductors for RF Transmitters in CMOS/MEMS Smart Microsensor Systems
Measured return loss characteristics (S11) of a fabricated antenna on silicon
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814858&req=5

f9-sensors-07-01387: Measured return loss characteristics (S11) of a fabricated antenna on silicon
Mentions: The output impedance of CMOS VCO has been well matched to 50Ω by inserting a passive matching element (series L, 27 nH). After the matching, the output power of the CMOS VCO became 1.09 dBm (=1.28 mW) at the same supply power. The power efficiency has become 50 % higher as compared to that before the matching. Although the matching was performed by a discrete component in this experiment, it is possible to be integrated on the same chip by extracting the proper value of the parameter from the experiment. Figure 9 shows the measured return loss characteristics before and after the impedance matching of the on-chip antenna fabricated on silicon. The center frequency was moved from 600-MHz to 300-MHz as a result of impedance matching. Also, the voltage standing wave ratio (VSWR) is improved by the matching procedure. The measured bandwidth with a VSWR better than 2.0 was approximately 247-to 351-MHz. This corresponds to the measured result of Figure 9.

View Article: PubMed Central

ABSTRACT

This paper presents the integration of an inductor by complementary metal-oxide-semiconductor (CMOS) compatible processes for integrated smart microsensor systems that have been developed to monitor the motion and vital signs of humans in various environments. Integration of radio frequency transmitter (RF) technology with complementary metal-oxide-semiconductor/micro electro mechanical systems (CMOS/MEMS) microsensors is required to realize the wireless smart microsensors system. The essential RF components such as a voltage controlled RF-CMOS oscillator (VCO), spiral inductors for an LC resonator and an integrated antenna have been fabricated and evaluated experimentally. The fabricated RF transmitter and integrated antenna were packaged with subminiature series A (SMA) connectors, respectively. For the impedance (50 Ω) matching, a bonding wire type inductor was developed. In this paper, the design and fabrication of the bonding wire inductor for impedance matching is described. Integrated techniques for the RF transmitter by CMOS compatible processes have been successfully developed. After matching by inserting the bonding wire inductor between the on-chip integrated antenna and the VCO output, the measured emission power at distance of 5 m from RF transmitter was -37 dBm (0.2 μW).

No MeSH data available.