This paper presents millimeter wave monolithic microwave integrated circuit (MMIC) low noise amplifiers using a 0.15 µm commercial pHEMT process. After carefully investigating design considerations for millimeter‐wave applications, with emphasis on the active device model and electomagnetic (EM) simulation, we designed two singleended low noise amplifiers, one for Q‐band and one for V‐band. The Q‐band two stage amplifier showed an average noise figure of 2.2 dB with an 18.3 dB average gain at 44 GHz. The V‐band two stage amplifier showed an average noise figure of 2.9 dB with a 14.7 dB average gain at 65 GHz. Our design technique and model demonstrates good agreement between measured and predicted results. Compared with the published data, this work also presents state‐of‐the‐art performance in terms of the gain and noise figure.
The phase noise reduction in a configuration of the HEMT oscillator with a dielectric resonator coupled by a quarter‐wavelength impedance inverter is investigated. Two HEMT oscillators for a satellite payload system are manufactured in the same configuration except for the coupling configuration of the dielectric resonator (DR) in order to empirically demonstrate the phase noise reduction. Experimental result shows that a phase noise reduction by 14 dB can be enhanced by increasing the characteristic impedance of a coupling microstrip impedance inverter.
An active frequency doubler monolithic microwave integrated circuit (MMIC) for E-band transceiver applications is presented in this letter. This MMIC has been fabricated in a commercial 0.1-μm GaAs pseudomorphic high electron mobility transistor (pHEMT) process on a 2-mil thick substrate wafer. The fabricated MMIC chip has been measured to have a high output power performance of over 13 dBm with a high fundamental leakage suppression of more than 38 dBc in the frequency range of 71 to 86 GHz under an input signal condition of 10 dBm. A microstrip coupled line is used at the output circuit of the doubler section to implement impedance matching and simultaneously enhance the fundamental leakage suppression. The fabricated chip is has a size of 2.5 mm × 1.2 mm. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ⓒ
A broadband monolithic microwave integrated circuit (MMIC) quadrature phase shift keying (QPSK) modulator with low amplitude and phase errors is proposed. The presented modulator adopts two wideband reflection-type binary BPSK modulators, each consisting of a modified Lange coupler with additional λ/4 transmission lines, varactor diodes, inductors and resistors. The proposed QPSK modulator is implemented in 0.15 μm GaAs low-noise pHEMT process. The measurements show an error vector magnitude and a demodulated I/Q offset <5.8% root-mean-square and −16.1 dB, respectively, from 18 to 26.5 GHz.Introduction: There have been many researches on modulators for direct-conversion architectures [1][2][3][4][5]. Despite there being various modulation specifications, one of the key design issues is the operational bandwidth to maintain a good error vector magnitude (EVM). One method to obtain good EVM is to use balanced architectures such as an active Gilbert cell-based modulator [1] and passive reflection-type modulators [2][3][4]. The Gilbert cell-based modulator has a compact size, but increases circuit complexity and power consumption. A more general modulator topology that can be used is a balanced reflectiontype modulator using push-pull or quadrature balanced schematics. However, these architectures require binary phase shift keying (BPSK) modulators to be well balanced and matched. In this Letter, a new monolithic microwave integrated circuit (MMIC) quadrature phase shift keying (QPSK) modulator using a modified Lange coupler with additional λ/4 transmission lines is proposed to achieve a broadband frequency range.
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