Chul Soon Park

PCS/W-CDMA dual-band MMIC power amplifier with a newly proposed linearizing bias circuit

A personal communications service/wide-band code division multiple access (PCS/W-CDMA) dual-band monolithic microwave integrated circuit (MMIC) power amplifier with a single-chip MMIC and a single-path output matching network is demonstrated by adopting a newly proposed on-chip linearizer. The linearizer is composed of the base-emitter diode of an active bias transistor and a capacitor to provide an RF short at the base node of the active bias transistor. The linearizer enhances the linearity of the power amplifier effectively for both PCS and W-CDMA bands with no additional DC power consumption, and has negligible insertion power loss with almost no increase in die area. It improves the input 1-dB gain compression point by 18.5 (20) dB and phase distortion by 6.1/spl deg/ (12.42/spl deg/) at an output power of 28 (28) dBm for the PCS (W-CDMA) band while keeping the base bias voltage of the power amplifier as designed. A PCS and W-CDMA dual-band InGaP heterojunction bipolar transistor MMIC power amplifier with single input and output and no switch for band selection is embodied by implementing the linearizer and by designing the amplifier to have broad-band characteristics. The dual-band power amplifier exhibits an output power of 30 (28.5) dBm, power-added efficiency of 39.5 % (36 %), and adjacent channel power ratio of -46 (-50) dBc at the output power of 28 (28) dBm under 3.4-V operation voltage for PCS (W-CDMA) applications.

A Dual-band CMOS RF Front-end for 2.4/5.2 GHz Applications

A dual-band RF front-end operating at 2.4 and 5.2 GHz is proposed. The dual-band RF front-end consists of a low noise amplifier and a single balance mixer which can be switched to operate at 2.4 and 5.2 GHz with the same hardware. In order to get the good performances at both frequency bands, the LNA uses a switched effective inductance in the input matching. The proposed RF front-end is designed with the 0.18 mum CMOS process with a supply voltage of 1.8 V while dissipating a power of 16 mW. The front-end has conversion gains of 28 dB and 32 dB, DSB noise figure of 3.9 dB and 3.1 dB at 10 MHz with RF frequency of the 2.4 GHz and 5.2 GHz, respectively

60GHz Rotman lens and new compact low loss delay line using LTCC technology

In this work, the first μ-strip 60GHz Rotman lens and new compact low loss strip delay line using low temperature co-fired ceramic(LTCC) are proposed. The lens has 3 steering capability for +26°, −26°, 0.1° angle, − 10.86dB of side lobe level(SLL), and 28° of half power beam width (HPBW). The Rotman lens is designed in μ-strip structure for integration capability with the system on package(SoP). In order to replace bulky and lossy meander line of the Rotman lens, new compact low loss delay line is developed and verified. It shows remarkable performance; it has smaller insertion loss. Furthermore, It shows 78% of length reduction than meander line. Also, owing to its simple and symmetrical structure, the delay line is reciprocal and analogous.

Low-voltage, Low-power and High-gain Mixer Based on Unbalanced Mixer Cell

A low-voltage, low-power and high-gain mixer core structure based on the unbalanced mixer cell or square-law mixer cell for 5GHz wireless LAN applications is presented in this paper. To reduce power dissipation, a new single-balanced mixer was proposed which operates under a low supply voltage and with the current reuse technique. The circuit was designed with a 0.18mum CMOS process. The designed down-conversion mixer has a maximum conversion gain of 22dB with LO power of -2.5dBm. However, with small LO power of -10dBm, -15dBm and -20dBm the mixer shows a moderate conversion gain of 14.9dB, 10dB and 5.1dB, and an input P1dB of -14dBm, -9.5dBm and -4.5dBm, and an input IP3 of -4.5dBm, 0dBm and 5dBm, respectively. The designed mixer including a bias circuit consumes 1.2mA under a 1.5V supply voltage. The chip size including pads is 0.77mm times 0.81mm

Dual-band LNA for 2.4/5.2GHz applications

A dual-band low noise amplifier (LNA) which can operate at both 2.4GHz and 5.2GHz frequency band is proposed. Input matching, noise matching and narrow gain are achieved at 2.4GHz and 5.2GHz frequency band by switching the equivalent inductance and resistance of input and output circuits. The proposed LNA is designed in a TSMC 0.18um CMOS technology with a supply voltage of 1.5V. The LNA has gain of 11.8 dB and 16 dB, noise figure of 3.6 dB and 2.5 dB at 2.4GHz and 5.2GHz frequency band respectively while dissipating power of 4.5 mW at both frequency bands.

A 5.8 GHz SiGe HBT direct-conversion I/Q-channel sub-harmonic mixer for low power and simplified receiver architecture

This paper presents a novel SiGe HBT sub- harmonic direct-conversion mixers for C-band wireless LAN application. The proposed down conversion mixer consists of single level I/Q-channel mixers and 90° phase shifters for each RF and LO input. Since the proposed sub-harmonic mixer requires only single ended RF and LO signal sources for generating I/Q base-band signals, the RF front-end can be greatly simplified compared to the fully differential RF front-end architecture from LNA and VCO to mixer. The measured conversion gain and input P1dB are 13.6 dB and -15 dBm, respectively at 5.8 GHz RF signal and 2.9 GHz LO signal. I/Q mismatches caused by LO and RF 90° phase shifters and I/Q- channel mixers are less than 5° and 0.5 dB in phase and amplitude mismatches. Each I/Q-channel sub-harmonic mixer consumes 6.2 mA from a 2.7 V supply.

Cellular/PCS dual-band MMIC power amplifier of a newly devised single-input single-chain network

This paperproposes a novel structure of single-input/chain dual-band power amplifier and reports the InGaP/GaAs hetero-junction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) power amplifier implemented for cellular (850 MHz)/PCS(l750 MHz) dual-band applications. This power amplifer has a single-input port to comply with multiband RF and has a single-chain network to achieve a small chip and module size. In order to reduce quiescent currents for cellular band, the band selecting circuit to control bias current is used to each of drive.andpower stage. The two-stage amplifier has a maximum output power of 30dBm (29dBm) and power-added efficiency (PAE) of 42%(37%) and adiacent channel power ratio(ACPR) of -5ldBc(-48dBc) at the output power of 28dBm(28dBm) under 3.4V operation voltage for cellular (PCS) band.

Vialess Coplanar Probe Pad-to-Microstrip Transitions for 60 GHz-band LTCC Applications

Compact and low-radiation CPW probe pads using CBCPW-to-microstrip transitions are demonstrated for V-band LTCC applications. To reduce the radiation loss due to open-end and transition discontinuities, a vialess CBCPW and back pad are designed. The back pad and an optimum transition length suppress the radiation loss due to discontinuities by 30 and 10 %, respectively, compared to a conventional vialess transition. In particular, the radiation loss of the designed transition is suppressed completely at 66 GHz and its S21 is -0.15 dB at that frequency

LTCC SoP integration of 60 GHz transmitter and receiver radios

This paper presents the 60 GHz SoP research activities including the integration and demonstration of a transmitter (Tx)/receiver (Rx) radio as well as design and fabrication of mmW sub-circuits such as low loss transmission lines and transitions with air cavities, a resonator, filters, and antennas, all in LTCC multilayer circuits.

A GCPW to waveguide transition in 60GHz LTCC SiP

This paper proposes a low loss and broadband grounded coplanar waveguide (GCPW) to waveguide (WG) transition in a low temperature co-fired ceramic (LTCC) multi-layer structure for 60GHz applications. The GCPW and WG are fully integrated on the same substrate, and the ground wall of the embedded WG is made up of a staggered via fence. A 3λ/4 bent short stub is connected between signal line of GCPW and WG ground wall for effective coupling. The WG dimension is gradually increased for broadband characteristic. Measured results for a single transition show that the insertion loss is 0.775dB at 58.3GHz and the 3-dB bandwidth is 6.8GHz from 53.1GHz to 59.9GHz. The proposed transition structure has been packaged in 60GHz LTCC System-in-Package(SiP) receiver module, and a 60GHz wireless data link at 648Mbps over 3m has been demonstrated.