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The poisoning effects of KCl and As2O3 on selective catalytic reduction (SCR) of NH3 with NO over Mn-Ce/AC catalysts were investigated with the reaction temperature range of 100–250 °C. KCl and As2O3 poisoned catalysts were synthesized by impregnation method and catalytic activity test was performed under the condition of simulated flue gas. The changes of crystal structure, microstructure, surface atomic state, surface acidity and functional groups were characterized by XRD, SEM, BET, XPS, NH3-TPD and FT-IR. Deactivation for single KCl or As2O3 doping catalyst was observed and severe synergistic inactivation occurred with the common effect of KCl and As2O3 on the catalyst. KCl destroyed the porosity of active carbon (AC) and could react with OH and C O on the surface of AC to ultimately form -O-K and Cl-C-O-K, resulting in the decrease of NH3 and NO adsorption. Besides, KCl caused the reduction of oxygen vacancies and chemisorbed oxygen on the Mn-Ce/AC catalyst. Lattice oxygen of MnOx may be transformed to surface chemisorbed oxygen to oxidize As2O3. As2O3 was oxidized to As2O5 and some layer was formed on the surface of catalyst preventing NH3 and NO adsorption. In addition, As2O3 could increase the number of oxygen vacancies and decrease the surface acidity of Mn-Ce/AC catalyst. According to the experimental results and theoretical analysis, the synergy poisoning model of KCl and As2O3 on Mn-Ce/AC catalysts was schematically established.

In this paper, channel spatial characteristics which mainly depend on the spatial correlation are selected as the significant factors in over-the-air (OTA) testing for multiple input multiple output (MIMO) devices. The multi-probe anechoic chamber method, a promising candidate of the MIMO OTA testing methods, can reproduce the multipath environments in a controllable manner. A novel physical configuration based on the variation of relative positions of probes in a MIMO OTA setup is put forward to obtain better spatial characteristics. Two physical configurations are presented to make a comparison with the typical configuration in this paper. The simulation results show that by making a proper probe configuration, good channel simulation accuracy can be achieved. Meanwhile, in order to get better performance of emulating channel spatial characteristics, probes in the first and the last probe rings should be placed symmetrically in three dimensional (3D) physical probe configuration.

This paper proposes a low-cost hardware architecture based on concurrent dual-band digital pre-distorter (DPD). The architecture is implemented on field programmable gate array (FPGA) to compensate for the nonlinearity of the concurrent dual-band power amplifier (PA). This implementation introduces a novel model complexity reduction technique into system, namely, time-division multiplexing for out-of-band lookup tables (LUTs) sharing. Performances are evaluated with an experimental test setup using a wideband class-F PA. The dual-band signal center frequency separated by 80 MHz. Lower and upper center frequency are located at 2.61 GHz and 2.69 GHz, respectively. This novel DPD implementation maintains excellent performance, but uses hardware resources reduced by 29.17% compared with conventional approaches. The results show that the adjacent channel power ratio (ACPR) is less than 59 dBc and normalized mean square error (NMSE) is around 62dB for lower sideband (LSB) and 63dB for upper sideband (USB).

This paper studies the behaviors of power amplifier (PA) driven by a single-carrier continuous wave (CW) signal and a two-carrier CW signal both in theory and simulation, and explains why the traditional dual-band PA failed to perform satisfactory results when a two-carrier CW signal is applied to, called concurrently. Besides that, an evaluation standard of concurrent dual-band PA was presented to value its performance. Solution was given with design and fabrication of a concurrent 1.85 GHz/2.65 GHz class F PA, employing a 10W GaN HEMT device from Cree, CGH40010, whose measurement shows the saturated output power is 40.6 dBm and 40.8dBm with drain efficiencies (DE) of 77.4% and 75.3% at 1.85 GHz and 2.65 GHz, respectively. On the other hand, we see that the peak DE achieves 59.7% with an output power of 39.9 dBm in concurrent mode, which follows up with the standard.

A new compact bandpass filter based on two meandered parallel-coupled lines of different lengths in shunt is presented, using the signal-interference technique, this filter obtains a low insertion loss and sharp rejection. A set of analytical formulas and guidelines for the design of the bandpass filter are provided in two theoretical analysis methods. According to the number of attenuation poles of the reflection coefficients in the passband, it can be summed up two types of filters. To validated this topology, two wideband bandpass filters centered at 3 GHz are built to verify the theoretical prediction, the measured frequency response of the filter agrees excellently with the predicted result.

A triangular memory polynomial (TMP) predistorter is presented in this paper to linearize a power amplifier's nonlinear with memory effects. Compared with the traditional memory polynomial (MP) predistorter, the coefficients of TMP predistorter is reduced more than 75%, which can effectively decrease the implementation complexity. The coefficients of predistorter are directly extracted from an offline system identification process by an open-loop structure in our approach. Several signals with data rate 5 MHz, 10 MHz, 15 MHz and 20 MHz are used to verify the performance of the proposed predistorter. Experimental results show that the proposed TMP predistorter and the traditional MP predistorter almost have the same performance.