Micro-Coaxial Impedance Transformers

In this paper, design, implementation, and experimental results of efficient, high-power, and multi-octave gallium nitride-high electron mobility transistor power amplifier are presented. To overcome the low optima source/load impedances of a large transistor, various topologies of a broadside-coupled impedance transformer are simulated, implemented, and measured. The used transformer has a flat measured insertion loss of 0.5 dB and a return loss higher than 10 dB over a decade bandwidth (0.4–4 GHz). The transformer is integrated at the drain and gate sides of the transistor using pre-matching networks to transform the complex optima source/load impedances to the appropriate impedances of the transformer plane. The measurement results illustrate a saturated output power ranged between 80 and 115 W with an average drain efficiency of 57% and gain of 10.5 dB across 0.6–2.6 GHz.

show abstract

“…(1) Lumped element transformers, (2) Coaxial and micro-coaxial transformers [10], (3) Planar transformers [12].…”

Section: I T R a N S F O R M E R D E S I G N A P R O A C Hmentioning

confidence: 99%

Multi-Octave bandwidth, 100 W GaN power amplifier using planar transmission line transformer

Arnous

Zhang

Rautschke

et al. 2017

Int. J. Microw. Wireless Technol.

View full text Add to dashboard Cite

show abstract

“…The small resonant feature that appears at 7.5 GHz in both simulations is due to a small length difference of the two main transmission lines caused by the series interconnection at the high-impedance end. This phenomena creates a path for a weakly-coupled shorted resonator within the transformer, allowing a small resonance feature to appear [7].…”

Section: A 5:1 Impedance Transformer Designmentioning

confidence: 99%

Broadband Planar 5:1 Impedance Transformer

Ehsan

Hsieh

Moseley

et al. 2015

IEEE Microw. Wireless Compon. Lett.

Self Cite

View full text Add to dashboard Cite

This letter presents a broadband Guanella-type planar impedance transformer that transforms 50 to 10 with a 10 dB bandwidth of 1-14 GHz. The transformer is designed on a flexible 50 thick polyimide substrate in microstrip and parallel-plate transmission line topologies, and is inspired by the traditional 4:1 Guanella transformer. Back-to-back transformers were designed and fabricated for characterization in a 50 system. Simulated and measured results are in excellent agreement.

show abstract

“…Unfortunately, the commonly used semi‐rigid coaxial transmission lines and especially ferrite cores are typically not suitable in the GHz range. Recent developments have presented topologies implementing impedance transformers, such as micro‐coaxial system , Marchand Baluns or broadside coupled printed circuit boards (PCB) , up to Ka‐ or even K‐band frequencies with double octave to decade bandwidths.…”

Section: Introductionmentioning

confidence: 99%

Double octave L- and S-band power amplifier utilizing broadside coupled impedance transformers

Preis

2015

Int J RF and Microwave Comp Aid Eng

View full text Add to dashboard Cite

In this article, the recently revived impedance transformer, implemented as broad side coupled microstrip structure, is used to realize a double octave wideband power amplifier covering the L-and S-band. Several parameters of the transformer, such as distance to a ground plane or permittivity of the dielectric surrounding the transformer are analyzed. The manufactured amplifier, using a commercial GaN HEMT transistor, achieved a continuous wave output power of 45 to 47 dBm and drain efficiency of 42 to 49 percent, respectively. To prove the usability of the concept, linearity measurements were performed, using LTE, WiMAX, and WCDMA signals with up to 10 MHz bandwidth at several center frequencies. ACLR results of 245 dBc are achieved using linearization, as well as an average PAE of up to 29 percent. V C 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:209-216, 2016.

show abstract

Micro-Coaxial Impedance Transformers

Cited by 20 publications

References 10 publications

Multi-Octave bandwidth, 100 W GaN power amplifier using planar transmission line transformer

Multi-Octave bandwidth, 100 W GaN power amplifier using planar transmission line transformer

Broadband Planar 5:1 Impedance Transformer

Double octave L- and S-band power amplifier utilizing broadside coupled impedance transformers

Contact Info

Product

Resources

About