Inkwon Ju

Ultra broadband DC to 40 GHz 5-bit pHEMT MMIC digital attenuator

A broadband, DC to 40 GHz 5-bit MMIC digital attenuator has been developed. The attenuator has been fabricated with 0.15 /spl mu/m GaAs pHEMT process. This attenuator has 1 dB resolution and 23 dB dynamic range. High attenuation accuracy has been achieved over all attenuation range and full 40 GHz bandwidth with the reference state insertion loss of less than 6 dB at 20 GHz. The input and output return losses of the attenuator are better than 14 dB over all attenuation states and frequencies.

High Performance Vertical Transition from DC to 70 GHz for System-on-Package Applications

High performance vertical transition from DC to 70 GHz was proposed for system-on-package (SoP) applications. The trough line, slab line and shielded multilayer coplanar waveguides were employed to minimize the radiation loss, crosstalk and discontinuity of a conventional via vertical transition. The half square via pad was used in order to prevent unwanted coupling between the transmission lines of the vertical transition. The proposed vertical transition was made using a LTCC process. The manufactured single vertical transition showed a low insertion loss less than 0.7 dB and a reflection loss below -13 dB in the frequency range of DC to 70 GHz.

Novel vertical transition using a trough line, a slab line and shielded multilayer coplanar waveguides for 50 GHz LTCC hermetic SMT MMIC package

A new vertical transition using a trough line, a slab line and shielded multilayer coplanar waveguides (SMCPW) was proposed in order to develop a DC to 50 GHz band low loss LTCC hermetic surface mounting (SMT) MMIC package. The trough line, the slab line and the SMCPWs were employed to minimize the radiation loss, crosstalk and discontinuity of the conventional via vertical transition. The proposed vertical transition was made with the multiple transmission lines that consist of the SMCPW1 -trough line -slab line -SMCPW2 -SMCPW3. The manufactured LTCC hermetic SMT MMIC package showed the low insertion loss less than 0.6 dB and the reflection loss below -20 dB in the frequency range from DC to 53 GHz.

A Low Power GaAs MMIC Multi-Function Chip for an X-Band Active Phased Array Radar System

An MMIC multi-function chip with a low DC power consumption for an X-band active phased array radar system has been designed and fabricated using a 0.5 GaAs p-HEMT commercial process. The multi-function chip provides several functions: 6-bit phase shifting, 6-bit attenuation, transmit/receive switching, and signal amplification. The fabricated multi-function chip with a compact size of exhibits a gain of 10 dB and a P1dB of 14 dBm from 7 GHz to 11 GHz with a DC low power consumption of only 0.6 W. The RMS(Root Mean Square) errors for the 64 states of the 6-bit phase shift and attenuation were measured to and 0.6 dB, respectively over the frequency.

Design and verification of SMT MMIC package using a 20 GHz LNA, a 40 GHz LNA and a 40GHz digital attenuator

A surface mounting (SMT) low temperature cofired ceramic (LTCC) MMIC package was developed using new vertical transition consist of a trough line, a slab line, and shielded multilayer coplanar waveguides (SMCPWs) for DC to 50 GHz band applications. A 20 GHz LNA, a 40 GHz LNA and a 40 GHz 5-bit digital attenuator were packaged to verify the performances of the developed LTCC SMT MMIC package. The packaged 20 GHz LNA has less than 0.3 dB gain degradation, compared with the on-wafer measurement. The packaged 40 GHz LNA has some differences with on-wafer measurement due to the size mismatch with the MMIC package. The packaged 40 GHz attenuator exhibits a negligible degradation of the attenuation accuracy, compared to the on-wafer results.

High Step Accuracy MMIC Channel Amplifier using Nonlinear Temperature Compensation for Ka-band OBS Satellite Transponder

*† This paper presents the design and the test results of the high step accuracy MMIC channel amplifier using the nonlinear temperature compensation for the Ka-band OBS satellite transponder. The channel amplifier RF section comprises two kinds of MMIC amplifiers, five MMIC attenuators, a coupler, a detector, a band pass filter and an isolator. The temperature compensated control circuit using PTC and NTC thermistors is proposed to compensate the nonlinear attenuation characteristics of the MMIC attenuators over temperature. To obt ain high step accuracy, the command word bits are modified correspondingly to the nonlinear attenuation characteristics of the MMIC attenuators versus control voltage. The test results show 32 dB settable gain control range, 16 dB output level control range, step accuracy of 1±0.3 dB and 1.2 dBp-p gain variation over temperature range in the operating frequency 19.8 GHz to 20.2 GHz.

Ku-band GaAs MMIC high power amplifier with high efficiency and broadband

In this paper, we present the GaAs PHEMT monolithic microwave integrated circuit (MMIC) high-power amplifier (HPA) with high efficiency and broadband. The HPA delivers 36 ~ 37dBm (4~5W) saturated output power with 28 ~ 31% power added efficiency (PAE) in the frequency band of 12 to 16 GHz, while providing 26~31 dB of small-signal gain and more than 42 dBm of output third-order intercept point (OIP3). This three-stage amplifier with chip size of 9.4mm2(4mm × 2.35mm) is designed to fully match 50-Ω input and output impedance.

The maintenance of HPA MMIC's efficiency for K-band

This paper describes methods of supporting efficiency of an HPA at K band. We designed and fabricated HPA MMIC for K band using UMS 0.25 um GaAs process and then added adaptive biasing circuits for preservation of HPA efficiency. The circuits for maintenance of PAE consist of a directional coupler, a RF detector, a buffer amplifier and a DC-DC convertor. The 8V supplied HPAs PAE is presented 13.5% at 32.3 dBm but adaptive bias supplied HPAs PAE is displayed 18.2% at Pout 31.9 dBm. The PAE of adaptive biased HPA increases 4.7% than 8 V supplied HPA. Also, the amplifier PAE is maintained at back off 3.5 dB in CW operation conditions. The MMIC power amplifier and adaptive biasing circuits for HPA MMICs efficiency are presented in this paper.

A GaAs MMIC Multi-Function Chip with a Digital Serial-to-Parallel Converter for an X-band Active Phased Array Radar System

An MMIC multi-function chip for an X-band active phased array radar system has been designed and fabricated using a 0.5 GaAs p-HEMT commercial process. A digital serial-to-parallel converter is included in this chip in order to reduce the number of the control interface. The multi-function chip provides several functions: 6-bit phase shifting, 6-bit attenuation, transmit/receive switching, and signal amplification. The fabricated multi-function chip with a relative compact size of 24 (6 mm4 mm) exhibits a transmit/receive gain of 24/15 dB and a P1dB of 21 dBm from 8.5 GHz to 10.5 GHz. The RMS errors for the 64 states of the 6-bit phase shift and attenuation were measured to and 0.3 dB, respectively over the frequency.

Qualification Model 4x4 Microwave Switch Matrix for the COMS Ka-band Communication Payload

[Abstract] This paper presents the design and test results of the Qualification Model 4x4 Microwave Switch Matrix (MSM) using PIN diode switches for the Communication, Oceanographic, and Meteorological Satellite (COMS) Ka-band communication payload. The parallel capacitance of a PIN diode restricts the isolation of the series PIN diode switch and the switch driver circuit limits the switching speed of PIN diode switch. The resonant circuitry and the TTL compatible switch driver circuit are proposed to obtain high isolation and high switching speed. High path isolation in the 4x4 MSM module was accomplished by using the appropriate interconnection cavity between 4-way power divider and SPST switch. The test results of the Qualification Model 4x4 MSM show that insertion loss is 16 dB, on-off isolation is more than 57 dB and on-off transition time is below than 30 ns.