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High-Efficiency Power Amplifiers
Published in Choi Jung Han, Iniewski Krzysztof, High-Speed and Lower Power Technologies, 2018
Guillermo Velasco-Quesada, Herminio Martínez‑García, Alfonso Conesa-Roca
In order to classify an amplifier as a high-power amplifier, it must be capable of handling large-signal amplitudes where the current and voltage swings may be a significantly large fraction of the bias value. Then, this classification can be carried out according to the portion of the period of the output waveform during which the circuit transistors conduct. The conduction angle of each transistor in the circuit, assuming a sinusoidal input, determines the designation of the amplifier. The amplifier classification by conduction angle for sinusoidal inputs is shown in Table 12.1. The output (collector or drain) current through a transistor for class-A, -B, -AB, and -C power amplifiers is shown in Figure 12.1.
MOSFETs for RF Applications
Published in Frank Schwierz, Hei Wong, Juin J Liou, Nanometer CMOS, 2010
Frank Schwierz, Hei Wong, Juin J Liou
High-power LDMOSFETs are not compatible with standard CMOS technology and thus have to be made as discrete devices. They are widely used in the high-power amplifiers for base stations of mobile communications systems. In fact, since the mid-1990s, discrete high-power Si LDMOSFETs are the devices of choice for base stations operating between 900 MHz and 2.7GHz, and have replaced all other competing power transistors (e.g., GaAs power MESFETs, HEMTs, and HBTs) in this field. These LDMOSFETs have very high breakdown voltages (up to more than 100 V), reasonably high output power densities (up to 1 W/mm), and very high output powers per transistor die (up to 50 W), see, for example Refs. 14, 52–55. If even higher output powers are needed, several dies can be combined to form power modules. Table 4.7 summarizes the state-of-the-art power performance of Si high-power LDMOSFETs. Three different criteria for the total output power Pout are indicated in the third column. Psat is the saturated output power. This is the maximum output power the transistor can deliver. Even if the input power is increased further, the output power will not rise beyond Psat. In real applications, the transistors are usually operated below Psat since under Psat operating conditions the gain and efficiency of the transistor are degraded. P–1 dB and P–3 dB are the output powers of the transistor at the so-called –1 dB and –3 dB compression points. At the –1 dB compression point, for example, the gain of the transistor has decreased by 1 dB below the small-signal power gain.
Analog and RF Performance Analysis and Its Sensitivity to Critical Geometrical Parameters in Junctionless Accumulation Mode Bulk FinFET
Published in Angsuman Sarkar, Arpan Deyasi, Low-Dimensional Nanoelectronic Devices, 2023
Kalyan Biswas, Angsuman Sarkar
To avoid SCEs, several device structures, that is, silicon-on-insulator (SOI) MOSFETs, double-gates MOSFETs, junction-less MOSFET, and multigate MOSFET, etc. are proposed.3 In comparison to the design of a transistor using single gate, the use of three gates around the Fin ensures tremendous electrostatic control on the channel.3 From the range of multi-gate MOSFETs, FinFETs are considered as the utmost popular structure in the area of 22-nm technology and above due to the lower short-channel effects and superior gate control compared to standard MOSFETs. These devices also provide the drain current ON/OFF rating and indicate the higher current drive compared to devices with planar structures. Because of these benefits, the industry has embraced FinFET technology as a mature technology.4 Junctionless MOSFET is another device with the same doping type for the semiconductor all the way starting from the source to the drain, which behaves as a resistor. Junctionless FETs have tougher protection against short-channel effects in comparison to FETs working in inversion mode. It is evident that there are many advantages of JL MOSFETs in comparison to standard devices that includes better protection from short-channel effects, greater scalability, improved DIBL, and so on.5, 6 The high reliability of a junctionless FET compared to inversion-mode FETs is shown by researchers. Unlike standard short-channel MOSFETs, formation of junctions is not required in JL MOSFETs thus reducing number of process steps. In addition, JL MOSFET can overcome many of the challenges of implementation such as controling doping level and also thermal budget. Accululation mode (JAM) FinFET-based FinFETs are developed and deployed.7, 8 The junctionless field-effect transistor was considered by lots of investigators8–12 as a suitable replacement for “highly scaled” devices. Recently, the p-channel junctionless accumulation-mode (JAM) MOSFET has been used successfully and has been reported.13 Ultra low-power (ULP) junctionless MOSFET performance in achieving advanced analog/RF metrics is also reported.11 The literature reveals that many of junctionless FinFETs show a good ON/OFF current ratio and better characteristics of short-channels effects.14 It is also shown that spacer usage can improve device performance. Recently, the research reports on the “junctionless-accumulation-bulk FinFETs” revealed that for devices using high-x gate spacers, efficiency of the device such as better DIBL, SS, and ION/IOFF ratio are obtained.8 For the application in wireless communication domain, there is a great need of high-power amplifier circuits, which should be capable of handling high power and high frequency. So, it is very much essential to evaluate the performance of the evolving new CMOS devices for its applicability in high-frequency analog/RF domain.15–21
Performance evaluation of MIMO DFT-Spread WR-OFDM system for spectrum efficiency and power efficiency
Published in Journal of Information and Telecommunication, 2022
High power amplifier (HPA) efficiencies for different modulation systems are depicted in Figure 9. In a practical wireless communication transmitter, HPA facilitates signal transmission over long distances. Since the PAPR of the suggested system is lower than the OFDM counterparts, the HPA efficiency is higher than conventional systems. From this figure, we can see that the maximum efficiencies of the OFDM system are 12.85% and 20.18% for Class A and B amplifiers, respectively. When WL = 4, the maximum efficiencies of the WR-OFDM system are 12.42% and 19.49% for Class A and B amplifiers, respectively. For the case of WL = 62, the maximum efficiencies of the WR-OFDM system are 12.13% and 19.05% for Class A and B amplifiers, respectively. The maximum efficiencies of the proposed system for WL = 4 are 15.81% and 24.82% for Class A and B amplifiers, respectively. And finally, for the case of WL = 62, the maximum efficiencies of the suggested system are 15.45% and 24.26% for Class A and B amplifiers, respectively.
Electromagnetic Simulation and Realization of MCM GaAs MMICs Based Packaging for High Gain (40 dB) and High-Power (33dBm) Transmitter Applications
Published in IETE Journal of Research, 2022
Ravi Gugulothu, Sangam Bhalke, Lalkishore K, Ramakrishna Dasari
The proposed dual cavity metal package is to integrate a driver amplifier (18 dB gain and 20 dBm power) with a power amplifier (20 dB gain and 2 W). This architecture forms a transmitter chain of a TRM module as shown in Figure 1. Advanced TRMs are divided into three blocks (Core-chips) based on the functionality of the MMICs as: Control block: This section contains a digital phase shifter, digital attenuator, and SPDT switch.Transmitter block: This section contains a driver amplifier and high power amplifier.Receiver block: This section contains low noise amplifier and gain blocks.
Development of 3DTV Emission Multiplexer and Reception-Signal Status Analyzer for ATSC 8-VSB & MDTV Hybrid 3DTV Services
Published in IETE Journal of Research, 2020
Sung-Hoon Kim, Dong-Wook Kang, Kyeong-Hoon Jung, Ki-Doo Kim
Figure 14 shows the head-end equipment setup in the SC-MMH 3DTV field trial. The test equipment comprises the encoder and stream generator, the multiplexer, the exciter, a high power amplifier (HPA) at the head-end side. Figure 15 shows the service coverage measuring vehicle in the SC-MMH 3DTV field trial. Figure 16 shows the test points and data of the signal measurements in the field trial. Figure 17 shows the service availability measured by the prototype signal status analyzer. Figure 18 displays the RF power spectrum and symbol constellation, measured by a commercial spectrum analyzer, at one of the signal measurement point wherein both the 8-VSB (left-eye channel) and MDTV (right-eye channel), are available. The field trial results verify all options of the SC-MMH 3D emission multiplexer and the reception-signal status analyzer. More specifically, all options successfully work with a commercial broadcasting system and the measuring instrument in a real broadcasting environment. The field trial results also verify the full backward compatibility of the proposed system with the current A/53 and A/153 standards [16].