Active Harmonic Load–Pull With Realistic Wideband Communications Signals

Abstract

A new wideband open-loop active harmonic load-pull measurement approach is presented. The proposed method is based on wideband data-acquisition and wideband signal-injection of the incident and device generated power waves at the frequencies of interest. The system provides full, user defined, in-band control of the source and load reflection coefficients presented to the device-under-test at baseband, fundamental and harmonic frequencies. The system capability to completely eliminate electrical delay allows to mimic realistic matching networks using their measured or simulated frequency response. This feature enables active devices to be evaluated for their actual in-circuit behavior, even on wafer. Moreover the proposed setup provides the unique feature of handling realistic wideband communication signals like multicarrier wideband code division multiple access (W-CDMA), making the setup perfectly suited for studying device performance in terms of efficiency, linearity and memory effects.In this work we describe the hardware and signal conditioning of the proposed setup. The high dynamic range, bandwidth and measurement speed of the system, together with its capability to engineer the large-signal operation of an active device, are demonstrated by measuring the improved RF performance of a multicarrier W-CDMA driven laterally diffused metal-oxide-semiconductor device when the electrical delay in the setup is canceled.

Enhanced RF power amplifiers and device characterization setups using coherent mixed-signal techniques

“…When using fully coherent signals as injection signals at the input and output port of an active device , basically an active open loop load-pull system is created [12] [16] . Note that such an approach, when based on mixed-signal techniques, provides absolute freedom for the content of the injection signals.…”

“…The related average PAE for this WCDMA signal with 11.8 dB crest factor was 53% [10]. The experience raised with the forgoing mixed-signal based amplifiers has triggered application of these new techniques in a novel open-loop active harmonic load-pull measurement system, which is capable to handle widebandmodulated signals in a realistic fashion [12]. The realized large-signal test bench provides full, user defined, in-band control of the source and load reflection coefficients presented to the device under test (DUT) at baseband, fundamental and harmonic frequencies.…”

Active harmonic source-/load-pull measurements of AlGaN/GaN HEMTs at X-band frequencies

“…Because of the requirement for high gain and power-efficiency at X-band 978-1-4799-4423-1/14/$31.00 ©2014 IEEE frequencies typically used for space applications as satellite or radar communication systems, the accurate measurement activity has to be accompanied with a highly performed technology. For this reason, the development of active harmonic loadpull measurement systems capable of presenting highly reflective fundamental and harmonic terminations at both the transistor input and output side [6][7] together with a systematic measurement procedure [8] needs to be accompanied with the continuous development of GaN technology capable of providing high performance at high frequency [9][10].…”

“…Figure I shows a simplified block diagram of the commercially available Anteverta MT2000 active harmonic loadpull system [6,13]. The test system covers the frequency range 0.5 -26.1 GHz and can handle 100 W of CW RF power at 2 GHz of fundamental frequency with the built-in test-set couplers and even more in pulsed mode.…”

“…1. Simplified block diagram of the commercially available Anteverta MT2000 mixedsignal active harmonic loadpull system[6,13].…”