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In this paper, the slow‐wave coplanar stripline (S‐CPS) technology is utilised to design high performance and small footprint resonators operating within the millimetre‐wave band from 50 to 80 GHz. The proposed resonators are designed based on high quality factor quasi‐lumped capacitances and inductances offering a great flexibility in terms of design. The derivation of these components from the S‐CPS is explained theoretically and their behaviour is validated by EM simulation; an equivalent electrical model is also developed. The proposed concepts are demonstrated in the BiCMOS 55‐nm technology, and a good agreement between modelling, EM simulation and measurement results is achieved. The proposed devices could later be considered as interesting elementary blocks for the design of mm‐wave filters. [ABSTRACT FROM AUTHOR]

The design and experimental results of millimeter-wave bandpass filters (BPFs) implemented in 55-nm BiCMOS technology and operating around 120 GHz are presented in this article. Slightly modified coupled line filters’ structures are used in the designs. It allows generating the transmission zero at the upper stopband, leading to the selectivity of enhanced filters. The coupled line structure is implemented in two technologies, microstrip coupled lines and coupled slow-wave (SW) coplanar waveguides (CS-CPWs). The latter shows more design flexibility, allowing to reach a better filtering performance than the microstrip filters, i.e., better in-band flatness and higher selectivity. Good agreement is achieved between simulation, modeling, and measurement results. Also, the overall length of the filter based on CS-CPWs is smaller as compared to the filters based on the microstrip lines, thanks to the SW propagation. [ABSTRACT FROM AUTHOR]

THz sources based on the optical-heterodyne (photo)mixing in an ultrafast photodetector are very promising since they operate at room temperature, are potentially compact, cost-efficient and, above all, are widely frequency-tunable. However, their widespread use is currently hampered by available power levels in the μW range at THz frequencies. We present here a travelling wave structure, with millimeter level coherence length at THz frequencies opening the way to large active area (∼4000 μm2) photomixing devices capable of handling optical pump power beyond 1 W well beyond the capabilities of standard lumped-element devices using small active areas (<50 μm2) needed to maintain a capacitance level (<10 fF) compatible with THz operation. It is based on a silicon nitride waveguide coupled to a membrane-supported low-temperature-grown GaAs photoconductor embedded in a coplanar waveguide. Milliwatt power levels up to 1 THz and still above 1 μW up to 4 THz are expected according to the optoelectronics model of this device elaborated in this study. Experimentally, the frequency response of a 1-mm-long structure, measured up to 100 GHz by using the beatnote produced by two 780-nm-DFB lasers, shows clearly the expected travelling wave signature consisting in a 6-dB-decrease ending at ∼50 GHz when the contribution of the backward travelling wave is fully cancelled, following by a constant level up to ∼100 GHz. The experimental demonstration of operation in the travelling wave regime is a first step towards the fulfillment of the original promises of this concept in terms of power level and frequency bandwidth. [ABSTRACT FROM AUTHOR]

This article focuses on the design of high-performance coupled slow-wave coplanar waveguide (CS-CPW) in CMOS technologies for the millimeter-wave (mm-wave) frequency bands. First, the theory as well as the electrical model of the CS-CPW are presented. Next, the analytical approach for the calculation of the model parameters is discussed. Then, by using the developed model, two mm-wave backward directional 3-dB couplers are designed in a bipolar complementary metal–oxide–semiconductor (BiCMOS) 55-nm technology for 120- and 185-GHz operation, respectively. Simulation and experimental results demonstrate that the use of the CS-CPW concept leads to state-of-the-art performance, with a good agreement between the analytical model, electromagnetic simulations, and measurement results. [ABSTRACT FROM AUTHOR]