Ted Rappaport, founding director of NYU WIRELESS and a leading proponent of using the millimeter wave spectrum for wireless communications, discusses the FCC's recent rulemaking actions and technology developments that are paving the way to 5G.
A generation ago, easy-to-use GaAs HBT based RF Gain Blocks changed the way RF engineers designed small signal amplifiers. That same evolution is now arriving in GaN technology with simple broadband solutions to medium power requirements in the 5 to 25 Watt range. This power range appears in a wide array of customer requirements, from output stages in broadband land-mobile and military handheld radios, small cell linear finals, to drivers in larger military, EW, and infrastructure power amplifiers. Entering the realm of power amplifiers though obviously brings new requirements and challenges, among them cost, size, power efficiency, and difficult thermal limitations that drive their electrical and package design. This paper will review conventional solutions, explore the tradeoffs between discrete and monolithic MMICs, and highlight the unique benefits of this new hybrid SMT solution.
Low noise amplifiers (LNAs) play a key role in radio receiver performance. The success of a receiver's design is measured in multiple dimensions: receiver sensitivity, selectivity, and proclivity to reception errors. The RF design engineer works to optimize receiver front-end performance with a special focus on the first active device. This paper considers device- and board-level variables that affect LNA performance and confront the engineer at each level of design in accommodating the various requirements of specific applications.
As more companies take advantage of the benefits of wireless technology, output device manufacturers must depend on highly linear, quality test equipment to meet those demands. Wireless communications encompass a number of applications.
Mobile network operating costs are driving the requirement for increased infrastructure efficiency, particularly in the final stage RF power amplifier. The venerable Chireix outphasing architecture proposed in 1936 by Henry Chireix has been updated with Gallium Nitride HEMT transistors operating in class E, and shown to deliver class leading efficiency.
Doherty combiner product line covers major
communication bands ranging from 700 MHz to 2700 MHz. Each model is optimized for the center
frequency of targeted frequency band. However, as new spectrum is being released, the preâdesigned standard models can be tuned in customer applications to
This document provides guidelines to tune these standard models for offâband applications.
Engineers who test mobile power amplifiers and front end modules are looking for ways to reduce test cost through maximizing throughput while ensuring that the devices meet required performance levels. This application note discusses these complex issues and recommended solutions using the Agilent PXI M9381A Vector Signal Generator as an example.
The mismatch between these real loads and the amplifier's output impedance result in a percentage of the forward power being reflected back to the amplifier. In some cases, excessive reflected power can damage an amplifier and precautions that may affect forward power are required. This Application note highlights the major RF amplifier characteristics that impact forward power as well as net power allowing the use of Ohm's law, even when conditions are far from ideal.
The published specifications for leakage current in RF power devices are often a source of concern and confusion for engineers and technicians. This paper examines the real meaning behind the leakage current specifications and offers guidance on properly testing a device for leakage current.
RFMD has developed 400W pulsed output power GaN
HEMT amplifiers operating over 2.9GHz to 3.5GHz band
or 17% bandwidth. Under pulsed RF drive with 10% duty
cycle and 100us pulse width, the amplifier delivers
output power in the range of 401W to 446W over the
band, with drain efficiency of 48% to 55% when biased at
drain voltage of 65V.