High-Power Microwave Filters

Vogelman, Joseph H.

doi:10.1109/tmtt.1958.1125220

Cited by 6 publications

(1 citation statement)

References 3 publications

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“…Cohn [4,5] reviewed the requirements of high-power filters and discussed various design approaches. Vogelman [6] and Whinnery [7] proposed varying-impedance waveguides and coaxial structures, where changes of the cross-sections of the wave guiding structures were tapered rather than abrupt. In all above high-power filter designs any corner was rounded and all surfaces were required to be especially smooth and polished, and free of contamination and irregularities.…”

Section: Comb-line Filtermentioning

confidence: 99%

High-power filters for switched-mode power amplifier systems

Serebryakova

Trabert

Blau

et al. 2009

2009 IEEE Radio and Wireless Symposium

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This paper presents the design and experimental characterisation of a coaxial comb-line band-pass filter for a switched-mode power amplifier (class-S), for an operating frequency of 450 MHz. The class-S amplifier architecture is laid out for very efficient amplification and high-power operation. Both requirements present challenges for the design of the reconstruction filter terminating the final stage. According to measurement results, an initially developed filter provided a bandwidth of 26 MHz, an insertion loss of 0.55 dB, and a second pass-band only at 2.8 GHz. The maximum input power handled by the filter amounted to 54 W, staying below the requirement. This power level was limited by electrical breakdown. Therefore, a highpower adaptation was devised and realised in an improved design subsequently. The resulting filter not only provided an even lower insertion loss of 0.37 dB but also handled more than 300 W input power. I. INTRODUCTIONRecently, the interest in increasing the power-added efficiency (PAE) of RF-and microwave power amplifiers in the final stage of a transmitter chain for mobile communications has grown significantly. The most efficient microwave power amplifiers operate in a switching mode, e.g., in class-S operation for input signals of arbitrary waveform. A switched-mode class-S power amplifier can provide high efficiency (> 70%) and, at the same time, high linearity, which makes it very attractive for, e.g., applications in mobile communications. Such an amplifier system consists of the following three basic building blocks, as indicated by Fig. 1 [1]: 1. A one-bit modulator, e.g., a pulse-length modulator (PLM) or a band-pass delta-sigma modulator (BDSM), maps the information contained in the high-frequency carrier signal into a train of pulses of variable length but constant amplitude. 2. A switching amplifier, possibly consisting of a driver and a push-pull final stage, provides the desired amplification by switching a bias source. 3. A band-pass filter is required for the reconstruction of the amplified signal. The output signal of the final stage of a class-S power amplifier includes noise-type signals from previous stages over a very broad frequency range. For the case of a BDSM, the output signal has a noise-like behaviour, whereas a PLM creates parasitic harmonics with significant power levels. Therefore, the band-pass filter has to provide not only extremely low insertion loss -an insertion loss of 1 dB reduces the overall efficiency by as much as 20 % -

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Section: Comb-line Filtermentioning

confidence: 99%

High-power filters for switched-mode power amplifier systems

Serebryakova

Trabert

Blau

et al. 2009

2009 IEEE Radio and Wireless Symposium

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Simple method for a K‐band SIW filter with dual‐mode quasi‐elliptic function response

Huang

Chang

Chen

et al. 2007

Micro & Optical Tech Letters

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A simple method for a K‐band substrate integrated waveguide (SIW) filter with dual‐mode response quasi‐elliptic function response is designed, fabricated, and measured around 20 GHz. By using an orthogonal input and output (I/O) feed‐line and adjusting a perturbation, the proposed filter with two transmission‐zeros are so close to the passband that the selectivity and out‐of‐band rejection of the filter are significantly increased. The designed filter demonstrates the superior passband characteristics with a measured central frequency fo = 20 GHz, the insertion loss S21 = −2.9 dB, the return loss S11 = −23.5 dB. Experimental results of the fabricated filter measured by network analyzer are well agreed with the simulation results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1246–1249, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22465

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Absorptive Filters for Microwave Harmonic Power

Met

1959

Proc. IRE

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High-Power Microwave Filters

Cited by 6 publications

References 3 publications

High-power filters for switched-mode power amplifier systems

High-power filters for switched-mode power amplifier systems

Simple method for a K‐band SIW filter with dual‐mode quasi‐elliptic function response

Absorptive Filters for Microwave Harmonic Power

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