Kwang-Jin Koh

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A four-element phased-array front-end receiver based on 4-bit RF phase shifters is demonstrated in a standard 0.18-mum SiGe BiCMOS technology for <i>Q</i>-band (30-50 GHz) satellite communications and radar applications. The phased-array receiver uses a corporate-feed approach with on-chip Wilkinson power combiners, and shows a power gain of 10.4 dB with an(More)
A 4-bit active digital phase shifter integrated with digital control circuitry in 0.13-mum CMOS technology is developed for K-band multiple antenna arrays. The active phase shifter synthesizes the required phase using a phase interpolation process by adding quadrature phased input signals. The phase shifter uses a resonance-based quadrature all-pass filter(More)
This paper demonstrates a 16-element phased-array transmitter in a standard 0.18m SiGe BiCMOS technology for Q-band satellite applications. The transmitter array is based on the All-RF architecture with 4-bit RF phase shifters and a corporate-feed network. A 1:2 active divider and two 1:8 passive tee-junction dividers constitute the corporate-feed network,(More)
This paper presents the design and analysis of an improved wideband in-phase/quadrature (I/Q) network and its implementation in a wideband phased-array front-end. It is found that the addition of two resistors (<i>R</i><sub>s</sub>) in the all-pass I/Q network results in improved amplitude and phase performance versus capacitance loading and frequency,(More)
This paper presents two 2-stage inverse class-F power amplifiers (PAs) at 24 GHz and 38 GHz, integrated in 0.13 μm SiGe BiCMOS technology. The PAs are composed of an inverse class-F output stage proceeded by a class-AB driving amplifier. An inter-stage matching network between the driver and output stage delivers an optimal inter-stage power to the output(More)
This paper presents a complete 8-element X/Kuband phased array based on a single silicon chip. The phased array is integrated together with the antennas and digital control circuitry on a single Teflon board. The chip-on-board package, together with 8 X/Ku-band RF inputs and one RF output in a 2.2x2.5mm area, and the appropriate grounding and Vcc(More)
This paper presents a Ku-band SiGe BiCMOS phased array receive chip capable of forming four-simultaneous beams from two antenna inputs. The design is based on the all-RF architecture with 4-bit active phase shifters and 4-bit variable gain amplifiers in each channel. The four-beam chip results in a gain of 4-6 dB per channel at 13-15 GHz, a noise figure of(More)
This paper presents an 8-element linear phased array receiver in 0.18-mum SiGe BiCMOS technology for X-and Ku-band applications. The array receiver adopts RF phase shifting architecture and the active 4-bit phase shifter synthesizes a phase by adding two properly weighted I-and Q-input. With all the digital control circuitry, bandgap reference and ESD(More)
This paper presents a 28 GHz class-F<sup>1</sup> power amplifier in 0.13-&#x03BC;m SiGe BiCMOS technology. The PA adopts a coupled-inductor based harmonic impedance modulator in order to terminate 2<sup>nd</sup> and 3<sup>rd</sup> harmonic load impedances appropriately for class-F<sup>1</sup> operation. The coupled coils essentially provide(More)