In this work, we study massive multiple-input multiple-output (MIMO) precoders optimizing power consumption while achieving the users’ rate requirements. We first characterize analytically solutions for narrowband and wideband systems minimizing amplifiers (PAs) in low system load, where per-antenna constraints are not binding. After, focus on asymptotic regime. The consumed by whole base stati...

in this paper, we investigate the parameters affecting total harmonic distortion (thd) and power supply rejection ratio (psrr) in pwm class d amplifiers (cdas) on the basis of linear models with feedback. from our mathematical analysis, we show that the thd of a pwm class d amplifier with feedback can be improved by increasing the gain of the integrator through adding another amplifier at the o...

The design of frequency-tunable amplifiers is investigated and the tradeoff between linearity, efficiency and tunability is revealed. Several tunable amplifiers using various varactor diode topologies as tunable devices are designed by using loadpull techniques and their performances are compared. The amplifier using anti-series distortion-free varactor stack topology achieves 38% power added e...

This letter presents a simple method to design dual-band high-efficiency power amplifiers (PAs). The coupler is exploited the output circuits of PA. By proper selection impedance conditions terminal ports, can convert fundamental transistor standard 50-Ω load at two frequencies. At same time, second harmonic also controlled without need for additional tuning. For validation, PA designed and fab...

The rapid evolution of wireless communication systems and the development of new standards require that wireless transmitters process several types of standards across multiple bands. Power amplifiers (PAs) are key components in wireless transmitters because they have a big impact on the overall system performance in terms of their bandwidth, efficiency, and linearity. This thesis presents vari...

In future mobile communication networks, there will be a shift towards higher carrier frequencies and highly integrated multiple antenna systems. The system performance will largely depend on the available RF hardware. As such, RF power amplifiers (PAs) with improved efficiency, linearity, and bandwidth are needed. Dynamic load modulation (DLM) is one of the most common PA efficiency enhancemen...

This paper presents a high-power microwave oscillator using recursive balanced amplification technique. The proposed architecture is configured by power amplifier (BPA) with class-AB operation and two feedback networks. Each circuit consists of phase shifter high-Q bandpass filter (BPF). BPA an input hybrid coupler (IHC) output (OHC) to divide recombine signals amplified through amplifiers (PAs...

The new Ka-band communications services require highly linear, high power amplifiers (HPAs). Traveling wave tube amplifiers (TWTAs) offer the best millimeter wave HPA performance in terms of power and efficiency, but are inferior to solid state power amplifiers (SSPAs) in linearity. This paper discusses techniques for improving millimeter wave HPA linearity. The significance and methods for eva...

Fujitsu has been developing gallium nitride high electron mobility transistors (GaNHEMT) for small transmitter amplifiers for Long Term Evolution (LTE) base stations. The use of GaN-HEMT in highly efficient transmitter amplifiers has attracted much attention because of its high breakdown voltage characteristics. High-efficiency amplifiers with high gain are needed to decrease the power consumpt...

The growth of in-car entertainment systems demands smart power devices, including audio power amplifiers. Despite the trend towards class-D systems, integrated class-AB amplifiers are still superior in terms of frequency response, integration level and ease of application. The market drive for lower distortion and higher stability demands good frequency compensation schemes. Still, to the best ...