FEM simulation of a small EB welded mock-up and new sequence proposed to improve the final distortions

In this paper, an Electron Beam (EB) welded mock-up is used for the calibration of the finite element method welding simulation developed. Once the method is validated, a new simulation welding sequence is proposed with the objective to reduce the mock-up final distortions. The final distortions should be reduced from 7 mm to 1 mm.Distortion measures and final deformed shapes are compared between two simulation scenarios to establish the effects of the new provisions assumed. The new simulation scenario includes a balanced longitudinal weld sequence in order to minimize the effects of the accumulative angular distortion process. The power of the FE method developed is demonstrated and will allow the optimization of the welding sequences to carry out previous simulation in FEM in future applications of ITER.     

CFD analysis of heat collection in a glazed gallery

A glazed gallery in most old buildings is a space located on the first floor (and/or higher floors), facing south and almost fully glazed. As a result of the large glazed area and the orientation of the gallery, its temperature is warmer than the exterior and, in cold weather, it is used both as a space to insulate the adjacent rooms and as a leisure area, among other applications. In the framework of the ARFRISOL project (Bioclimatic Architecture and Solar Cooling), a demonstration container has been constructed in northern Spain (Asturias) which includes, among other bioclimatic elements, a glazed gallery. This gallery is considered as an element of Bioclimatic Architecture that enables solar radiation to be collected and the energy obtained to be used to support the building's air conditioning system. It consists of a south-facing glazed exterior wall, an intermediate space or passage and a partially glazed interior wall. Dampers located in the floor and ceiling of the intermediate space and connected to the air ducts enable the air circulating inside the gallery to be heated or cooled, depending on the season of the year, before it is further conditioned and conveyed to the rooms. This paper focuses on the three-dimensional numerical simulation of the airflow inside the gallery. The aim is to obtain a model to evaluate the thermal energy obtained in this architectural feature, integrating the effect of certain variables, such as the incident solar irradiation, the outdoor temperature and the air flow rate circulating in the gallery.     

A millimeter‐wave CMOS power amplifier design using high‐Q slow‐wave transmission lines

A three‐stage 60‐GHz power amplifier (PA) has been implemented in a 65 nm Complementary Metal Oxide Semiconductor (CMOS) technology. High‐quality‐factor slow‐wave coplanar waveguides (S‐CPW) were used for input, output and inter‐stage matching networks to improve the performance. Being biased for Class‐A operation, the PA exhibits a measured power gain G of 18.3 dB at the working frequency, with a 3‐dB bandwidth of 8.5 GHz. The measured 1‐dB output compression point (OCP_1dB) and the maximum saturated output power P_sat are 12 dBm and 14.2 dBm, respectively, with a DC power consumption of 156 mW under 1.2 V voltage supply. The measured peak power added efficiency PAE is 16%. The die area is 0.52 mm² (875 × 600 μm²) including all the pads, whereas the effective area is only 0.24 mm². In addition, the performance improvement of the PA in terms of G, OCP_1dB, P_sat, PAE and the figure of merit using S‐CPW instead of thin film microstrip have been demonstrated. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:99–109, 2016.     

Tunable bandpass microwave filters based on defect commandable photonic bandgap waveguides

A new type of tunable filter based on a commandable defect in the bandgap of a periodic CPW structure is proposed. The defect level is tuned either mechanically by adding a covering slab over the device or electrically by polarising diodes located at the defect. The validity of this concept is experimentally demonstrated at 4 GHz. This kind of filter is well suited for applications in the 10 to 60 GHz frequency range.     

Improved and compact 0.7 GHz tune-all bandpass filter

A compact tune-all bandpass filter is presented. This electronically tuned filter is based on series-coupled slow-wave resonators. It allows wide simultaneous and continuous tunings of centre frequency (+/-15% around 0.7 GHz) and bandwidth (from 50 to 100 MHz) with insertion loss IL<5.4 dB and return loss RL>11 dB. This two-pole bandpass filter exhibits also a very small surface of only 7.3times10^-3 lambda₀ ² and a -20 dB stop-band that extends up to 10 GHz     

Compact and selective lowpass filter with spurious suppression

A novel coplanar-type compact and selective lowpass filter is proposed. It consists of a simple high-impedance transmission line loaded with capacitors. Spurs are completely suppressed, with an attenuation larger than 20 dB outside the passband. The return loss is greater than 16 dB in the passband and the attenuation slope is more than 500 dB/decade for a 0.6 /spl lambda/-long filter.