We report on an adjustable interferometric set-up for Scanning Microwave Microscopy. This interferometer is designed in order to combine simplicity, a relatively flexible choice of the frequency of interference used for measurements as well as the choice of impedances range where the interference occurs. A vectorial calibration method based on a modified 1-port error model is also proposed. Calibrated measurements of capacitors have been obtained around the test frequency of 3.5 GHz down to about 0.1 fF. Comparison with standard vector network analyzer measurements is shown to assess the performance of the proposed system.

We give an analytical and experimental demonstration of a classical analogue of the electromagnetic induced absorption (EIA) in a simple photonic device consisting of two stubs of lengths d1 and d2 grafted at the same site along a waveguide. By detuning the lengths of the two stubs (i.e. δ = d(2) - d(1)) we show that: (i) the amplitudes of the electromagnetic waves in the two stubs can be written following the two resonators model where each stub plays the role of a radiative resonator with low Q factor. The destructive interference between the waves in the two stubs may give rise to a sharp resonance peak with high Q factor in the transmission as well as in the absorption. (ii) The transmission coefficient around the resonance induced by the stubs can be written following a Fano-like form. In particular, we give an explicit expression of the position, width and Fano parameter of the resonances as a function of δ. (iii) By taking into account the loss in the waveguides, we show that at the transmission resonance, the transmission (reflection) increases (decreases) as a function of δ. Whereas the absorption goes through a maximum around 0.5 for a threshold value δth which depends on the attenuation in the system and then falls to zero. (iv) We give a comparison between the phase of the determinant of the scattering matrix, the so-called Friedel phase and the phase of the transmission amplitude. (v) The effect of the boundary conditions at the end of the resonators on the EIA resonance is also discussed. The analytical results are obtained by means of the Green's function method, whereas the experiments are carried out using coaxial cables in the radio-frequency regime. These results should have important consequences for designing integrated devices such as narrow-frequency optical or microwave filters and high-speed switches.

This article presents microelectromechanical system (MEMS) ground-signal-ground (GSG) probes based on silicon-on-insulator (SOI) technology for on-wafer microwave characterization of radio-frequency (RF) microelectronics. The probe is designed using optimized coplanar waveguide structures with the aim of ensuring a low-contact resistance between the probe and the pads of the device under test (DUT). The probes are batch fabricated using SOI substrates and employ a simple silicon micromachining process. The probes have a pitch of 4.5 µm with miniaturized dimensions for a DUT pad area with a similar size. Electrical (dc) measurements show that the fabricated probe has a low-contact resistance (~0.02 Ω) on gold pads. Excellent extracted RF performances of the probe are observed up to 30 GHz, showing an insertion loss better than 2.2 dB and return loss better than 20 dB over the frequency range. An ageing study shows the probes are capable of forming this dc contact for over 6000 contact cycles. The preliminary result of the repeatability of on-wafer one-port measurements with the miniaturized probe shows a consistent RF performance maintained through several contacts. The data indicates that the proposed MEMS probe is suitable for the high-frequency characterization of integrated nanoscale devices having reduced pad dimensions.

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We give an analytical and experimental demonstration of the possibility to realize a simple photonic demultiplexer based on electromagnetically induced transparency resonances. The demultiplexer consists of a Y-shaped waveguide with an input line and two output lines. Each output line contains two grafted stubs at a given position far from the input line. We derive in closed form the expressions for a selective transfer of a single propagating mode through one line keeping the other line unaffected. We illustrate the analytical and numerical results by a simple experiment carried out using coaxial cables in the radio frequency domain.

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