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 This paper proposes an efficient envelope delta-sigma based transmitter architecture with gate bias modulation for modern wireless communication systems. Using this architecture, envelope varying signals are converted to constant envelope signals. The constant envelope phase signal is up-converted and amplified utilizing high efficiency power amplifier, while the two level delta-sigma modulated envelope signal is used to switch the gate of the power amplifier. To validate the proposed technique, a prototype transmitter is implemented and evaluated. A Long-Term Evolution (LTE) uplink signal with the bandwidth of 3.84 MHz and the peak-to average power ratio (PAPR) of 7 dB is used to validate the linearity and efficiency performance of the transmitter setup. Using the LTE uplink signal, the polar architecture with modulated gate bias is able to achieve the average drain efficiency of 48% and PAE of 42% at the output power of 25.5dBm. The adjacent channel leakage ratio (ACLR) measured for this signal is less than -31dBc at 10 MHz offset from the center frequency of 2.35GHz. The measurement results are able to meet the spectrum mask without linearization techniques.

Goal:The purpose of this study was to investigate the factors affecting the purchasing decisions of consumers of green products.Design / Methodology / Approach: The sample of this study was composed of consumers of disposable products in Isfahan. In this study, Descriptive statistics is used for data analysis and Structural Equation Modeling is used test the research hypotheses and determine the effect of independent variables on the dependent variable. Results:Considering the critical values obtained from the research hypothesis test, it can be concluded that environmental protection, environmental responsibility, green product experience, environmentally friendly brands and social acceptance have a positive and significant effect on green product purchase decisions. Limitations of the investigation:Since the present study is an exploratory study, the findings of the study are limited to the sample and results may be changed if the sample is changed. Also, the sample of green product buyers' decisions was obtained from only one province, so the results may not be generalizable to all provinces of Iran. Practical implications:According to the results, it is recommended that environment-friendly companies differentiate their products from other products and price them appropriately. This should have an impact on consumers and encourage them to buy and use green products. Originality / Value:The design of the products in a recyclable form and making their components and materials reusable will in future cause their raw materials are recycled and reused; thus, buyers are more eager to buy green products with regard to environmental protection.

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