This paper presents a Ka-band high-efficiency power amplifier (PA) with a novel adaptively controlled gate capacitor circuit and a two-step adaptive bias circuit for 5th generation (5G) mobile terminal applications fabricated using a 45-nm silicon on insulator (SOI) CMOS process. The PA adopts a stacked FET structure to increase the output power because of the low breakdown voltage issue of scaled MOSFETs. The novel adaptive gate capacitor circuit properly controls the RF swing for each stacked FET to achieve high efficiency in the several-dB back-off region. Further, the novel two-step adaptive bias circuit effectively controls the gate voltage for each stacked FET for high linearity and high back-off efficiency. At a supply voltage of 4 V, the fabricated PA has exhibited a saturated output power of 20.0 dBm, a peak power added efficiency (PAE) of 42.7%, a 3dB back-off efficiency of 32.7%, a 6dB back-off efficiency of 22.7%, and a gain of 15.6 dB. The effective PA area was 0.82 mm by 0.74 mm.

In this paper, a CMOS Class-G supply modulation for polar power amplifiers with high average efficiency and low ripple noise is proposed. In the proposed Class-G supply modulation, the parallel supply modulations which are controlled by switch signals are utilized for low power and high power supplies to increase the average efficiency. A low dropout (LDO) is utilized to suppress the delta-modulated noise and provide a low ripple noise power supply. The proposed supply modulation has high efficiency at large output current as the conventional supply modulation, and it also has high efficiency and low ripple noise at the low output current. To verify the effectiveness of the proposed supply modulation, the proposed supply modulation was designed with 0.13 µm CMOS process. The simulation results show that the proposed supply modulation achieves a maximum efficiency of 85.1%. It achieves an average efficiency of 29.3% and a 7.1% improvement compared with the conventional supply modulations with Class-E power amplifier. The proposed supply modulation also shows an excellent spurious free dynamic range (SFDR) of -73 dBc for output envelope signal.

A balanced push-push frequency doubler has been demonstrated in 0.25-µm SOI (Silicon on Insulator) SiGe BiCMOS technology operating from 22 GHz to 29 GHz with high fundamental frequency suppression and high conversion gain. A series LC resonator circuit is connected in parallel with the differential outputs of the doubler core circuit. The LC resonator is effective to improve the fundamental frequency suppression. In addition, the LC resonator works as a matching circuit between the output of the doubler core and the input of the output buffer amplifier, which increases the conversion gain of the whole circuit. A measured fundamental frequency suppression of greater than 46 dBc is achieved at an input power of -10 dBm in the output frequency band of 22-29 GHz. Moreover, maximum fundamental frequency suppression of 66 dBc is achieved at an input frequency of 13 GHz and an input power of -10 dBm. The frequency doubler works at a supply voltage of 3.3 V.

This paper presents a 28-GHz-band highly linear stacked-FET power amplifier (PA) IC. A 4-stacked-FET structure is employed for high output power considering the low breakdown voltage of scaled MOSFET transistors. A novel adaptive bias circuit is proposed to dynamically control the gate-to-source bias voltage for amplification MOSFETs. The novel adaptive bias allows the PA to attain high linearity with high back-off efficiency. In addition, the third-order intermodulation distortion (IM3) is improved by a multi-cascode structure. The PA IC is designed, fabricated and fully tested in 56-nm SOI CMOS technology. At a supply voltage of 4 V, the PA IC has achieved an output power of 20.0 dBm with a PAE as high as 38.1% at the 1-dB gain compression point (P1dB). Moreover, PAEs at 3-dB and 6-dB back-off from P1dB are 36.2% and 28.7%, respectively. The PA IC exhibits an output third-order intercept point (OIP3) of 25.0 dBm.

A novel resonant circuit consisting of transformer-based switched variable inductors and switched accumulation MOS (AMOS) varactors is proposed to realize an ultrawide tuning range voltage-controlled-oscillator (VCO). The VCO IC is designed and fabricated using 0.11 µm CMOS technology and fully evaluated on-wafer. The VCO exhibits a frequency tuning range as high as 92.6% spanning from 1.20 GHz to 3.27 GHz at an operation voltage of 1.5 V. The measured phase noise of -120 dBc/Hz at 1 MHz offset from the 3.1 GHz carrier is obtained.

A broadband balanced frequency doubler has been demonstrated in 0.25-µm SOI SiGe BiCMOS technology to operate from 22 GHz to 30 GHz. The measured fundamental frequency suppression of greater than 30 dBc is achieved by an internal low pass LC filter. In addition, a pair of matching circuits in parallel with the LO inputs results in high suppression with low input drive power. Maximum measured conversion gain of -6 dB is obtained at the input drive power as low as -1 dBm. The results presented indicate that the proposed frequency doubler can operate in broadband and achieve high fundamental frequency suppression with low input drive power.

This paper presents two ultra-low voltage and high performance VCO ICs with novel harmonic tuned LC tank which provides different harmonic impedance and shapes the pseudo-square drain voltage waveform of transistors. In the novel tank, two additional inductors are connected between the drains of the cross-coupled pMOSFETs and the conventional LC tank, and they effectively decrease second harmonic load impedance and increase third harmonic load impedance of the transistors. In this paper, the novel harmonic tuned LC tank is applied to two different structure VCOs. These two VCOs exhibit over 2 dB better phase noise performance than conventional LC tank VCOs among all tuning range. The conventional and proposed VCO ICs are designed, fabricated and measured on wafer in 45-nm SOI CMOS technology. With novel harmonic tuned LC tank, the novel two VCOs exhibit measured best phase-noise of -125.7 and -129.3 dBc/Hz at 10 MHz offset and related FoM of -190.2 and -190.5 dBc/Hz at a supply voltage of 0.3 V and 0.35 V, respectively. Frequency tuning range of the two VCOs are from 13.01 to 14.34 GHz and from 15.02 to 16.03GHz, respectively.

This paper presents high efficiency Class-E and compact Doherty power amplifiers (PAs) with novel harmonics termination for handset applications using a GaAs/InGaP heterojunction bipolar transistor (HBT) process. The novel harmonics termination circuit effectively reduces the insertion loss of the matching circuit, allowing a device with a compact size. The Doherty PA uses a lumped-element transformer which consists of metal-insulator-metal (MIM) capacitors on an IC substrate, a bonding-wire inductor and short micro-strip lines on a printed circuit board (PCB). The fabricated Class-E PA exhibits a power added efficiency (PAE) as high as 69.0% at 1.95GHz and as high as 67.6% at 2.535GHz. The fabricated Doherty PA exhibits an average output power of 25.5dBm and a PAE as high as 50.1% under a 10-MHz band width quadrature phase shift keying (QPSK) 6.16-dB peak-to-average-power-ratio (PAPR) LTE signal at 1.95GHz. The fabricated chip size is smaller than 1mm2. The input and output Doherty transformer areas are 0.5mm by 1.0mm and 0.7mm by 0.7mm, respectively.

This paper presents a novel CMOS bias topology serving as not only a bias circuit but also an adaptive linearizer for SiGe HBT power amplifier (PA) IC. The novel bias circuit can well keep the base-to-emitter voltage (Vbe) of RF amplifying HBT constant and adaptively increase the base current (Ib) with the increase of the input power. Therefore, the gain compression and phase distortion performance of the PA is improved. A three-stage 5-GHz band PA IC with the novel bias circuit for WLAN applications is designed and fabricated in IBM 0.35µm SiGe BiCMOS technology. Under 54Mbps OFDM signal at 5.4GHz, the PA IC exhibits a measured small-signal gain of 29dB, an EVM of 0.9% at 17dBm output power and a DC current consumption of 284mA.

This paper presents a 26-GHz-band high back-off efficiency power amplifier (PA) IC with adaptively controlled bias and load circuits in 45-nm CMOS SOI. A 4-stacked-FET is employed to increase the output power and to conquer the low breakdown voltage issue of scaled MOSFET. The adaptive bias circuit is reviewed and the adaptive load circuit which consists of an inverter circuit and transformer-based inductors is described in detail. The measured performance of the PA IC is fully shown in this paper. The PA IC exhibits a saturated output power of 20.5dBm and a peak power-added-efficiency (PAE) as high as 39.4% at a supply voltage of 4.0V. Moreover, the PA IC has exhibited an excellent ITRS FoM of 82.0dB.

This paper presents two ultra-low voltage and high performance VCO ICs with two novel transformer-based harmonic tuned tanks. The first proposed harmonic tuned tank effectively shapes the pseudo-square drain-node voltage waveform for close-in phase noise reduction. To compensate the voltage drop caused by the transformer, an improved second tank is proposed. It not only has tuned harmonic impedance but also provides a voltage gain to enlarge the output voltage swing over supply voltage limitation. The VCO with second tank exhibits over 3 dB better phase noise performance in 1/f2 region among all tuning range. The two VCO ICs are designed, fabricated and measured on wafer in 45-nm SOI CMOS technology. With only 0.3 V supply voltage, the proposed two VCO ICs exhibit best phase noise of -123.3 and -127.2 dBc/Hz at 10 MHz offset and related FoMs of -191.7 and -192.2 dBc/Hz, respectively. The frequency tuning ranges of them are from 14.05 to 15.14 GHz and from 14.23 to 15.68 GHz, respectively.

A fully integrated voltage controlled oscillator (VCO) MMIC for millimeter-wave applications has been designed and implemented in InGaP/GaAs heterojunction bipolar transistor (HBT) technology. To achieve a fully integrated VCO, a base-emitter diode is employed as the tuning varactor, and microstrip lines are employed for the transmission lines. The fabricated VCO MMIC chip size is 0.86 mm 1.34 mm and delivers an output power of 5.1 dBm at 28.7 GHz and a free-running phase noise of -118 dBc/Hz at 1 MHz offset. The dc current consumption is only 20 mA.

A 5-GHz-band highly linear frequency tuning voltage-controlled oscillator (VCO) using 0.35 µm SiGe BiCMOS technology is presented. The highly linear VCO has a novel resonant circuit that includes two spiral inductors, p-n junction diode varactor units and a voltage-level- shift circuit. The fabricated VCO exhibits a VCO gain from 224 to 341 MHz/V, giving a Kvco ratio of 1.5, which is less than one-half of that of a conventional VCO. The measured phase noise is -116 dBc/Hz at 1 MHz offset at an oscillation frequency of 5.5 GHz. The tuning range is from 5.45 to 5.95 GHz. The dc current consumption is 3.4 mA at a supply voltage of 3.0 V.