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A novel electromagnetic bandgap power/ground (P/G) network is proposed by using λ/4 open stub resonators for the broadband suppression of the simultaneous switching noise. Since three λ/4 open stub resonators are linked to the bridge between the two cells as bandstop filter, the high‐order mode resonances can be effectively suppressed. The proposed P/G network is analyzed by the cavity modes, simulated by the full‐wave simulator, and validated by the measurement. A broadband simultaneous switching noise suppression from 0.6 to 7.6 GHz is achieved. Additionally, in comparison with the reference boards, the radiated emission has less electromagnetic interference, which validates the advantage of the proposed electromagnetic bandgap P/G network. [ABSTRACT FROM AUTHOR]

The authors demonstrate a high‐speed 8.5‐μm quantum cascade laser (QCL) with room temperature continuous wave (CW) operation. The maximum output power of 141 mW is obtained at 20°C. The parasitic capacitance of the device is decreased from 36.6 to 7.1 pF by monolithic integrating a π‐shape metal contact electrode. This results in an increase in the −3 dB RF modulation bandwidth from 870 MHz to 4.5 GHz compared with the conventional electrode configuration. [ABSTRACT FROM AUTHOR]

A coupled line schematic is proposed to build the differential filter featuring broadband, low insertion loss and good common‐mode suppression. The proposed filter is composed of four quarter‐wavelength coupled lines and four quarter‐wavelength microstrip lines. The calculated, simulated and measured results are in good agreement with each other. The differential‐mode signal can propagate with low insertion loss, whereas the common‐mode signal will be suppressed below −10 dB. The fractional bandwidth of the proposed filter is 82% centred at 3 GHz. [ABSTRACT FROM AUTHOR]