【正文】 mentsThe source pull of the fundamental impedance did increase the output power and efficiency of amplifier C slightly. The optimum drain efficiency (circles) and output power points(triangles) (a) and (b), respectively, are shown Fig. 17. The power points are within the limits of dB and efficiency within a difference of 2% units. The amplifier efficiency rose with the fundamental source tuning to % (point a)and the output to about W ( dBm, point b). Harmonic source pull measurements showed that the harmonic impedances were not as critical as the fundamental. This is due to the low pass input matching and the wideband RCsink circuit. The RCsink circuit lowers the calculated magnitude of the impedance especially at high frequencies,as shown in (b). This has an effect to both second and third harmonic impedances. The magnitude of the impedance without the RCsink is shown as a reference in (a). In both cases the input matching circuits were not included in the calculations. Stability of the amplifier At first the amplifier A did show some unstable behaviour due to supply voltage modulation caused by insufficient bias decoupling at the drain. The instability appeared at low input power levels as noise sidebands that lied on both sides of fundamental frequency. When input power was lowered further on, the amplifier did break into full scale oscillation. As a cure, the supply impedance was lowered by a large number of decoupling capacitors (4 470 pF)added to the drain. In an EER application, the supply modulator will provide low enough impedance at the drain. When the load pull was done to the amplifiers A, C and D, a spurious oscillation detection was applied at a level of50 dBc. With this setup we were able to pare the sensitivity of different amplifiers to oscillations. We found out that the RCsink circuit used in amplifiers A and C indeed improved stability, especially in the low input power levels. Data used for parison was measured from amplifier D, where the RCsink was cut using an ultraviolet laser. The oscillation points of the fundamental impedance load pull with a low 15 dBm input power are shown in . The oscillation sidebands detected are1701 and 1489 MHz. If we pare this result to amplifier A, the amount of found oscillation points is considerably smaller and the location of them is rather tightly spaced in the low impedance area, as shown in Fig. 20. The oscillation frequency in this case is 1568 MHz. The amplifier A and amplifier D had a different frequency for the modulating spurious ponents: Without the damping circuit the modulating spurious was ca.177。電子科學與技術外文翻譯 班 級： 學 號： 姓 名： 指導教師： 時 間： 34 / 34 Design of integrated GHz, 2 W tuned RF power amplifier Abstract： This paper describes the design of an integrated tuned power amplifier specified to operate at Inmarsat satellite uplink frequencies from to basic topology of the amplifier lies on the parallel tuned inverse class E amplifier that is modified by placing the DCblocking capacitor into a new position and by adjusting the size of the capacitor to improve stability below the desired band. Further, the new positioning reduces losses between drain and load. The high currents flowing in the circuit made it necessary to use wide inductor width and highQ finger capacitors in the onchip resonator. The amplifier was implemented as a Gallium Arsenide (GaAs) integrated circuit (IC) that delivered 2 W of output power while the drain efficiency was ca. 56%.Measurements included source and load pulls to further improve the performance of the amplifier and to investigate the stability at small input drive levels.Keywords: Inverse class E?Power ? Bias network 1 IntroductionThe usability of traditional linear amplifiers in today’s high power munications systems is limited due to their low efficiency. This fact has driven the interest of research towards more efficient amplifiers such as class E [1–3] and inverse class E [4]. Also, the demand of higher output power means higher peak currents and voltages in the drain or collector circuits. This creates high requirements for both maximum breakdown values of the transistor and to the passive circuitry of the monolithic microwave integrated circuit (MMIC). The effect of limited conductivity and limited capability to cope with heat can be minimized through careful design of MMIC. Further, emerging transistor technologies seem to withstand larger current densities and peak voltages [5], and therefore, the choice of technology is increasingly important when designing high power devices. The aim of this paper is to show experiences related to the design of switching high power radio frequency(RF) amplifiers (PA) with integrated output pulse shaping. In the second chapter the introduction to class E and inverse class E operation is revisited and the differences between the two topologies are third chapter describes the design of the input and output circuitry, stabilizing circuits and provides some tips to minimize timing differences at the input of a multifinger transistor. The fourth chapter shows the final schematic and a photo of the implemented chip. The measured performance is reported in chapter five by using both basic single tone measurement equipment and a modern load pull system using multipurpose tuners(MPT). The last section provides a summary of the article and discussion of the issues related to stabilizing circuits. 2 Class E and inverse class E amplifiers Class E and inverse class E are regarded as switching amplifiers. Ideally, in both of them the transistor is driven either on or off and this switching o