Yoshihisa Amano

A High-Power Low-Distortion GaAs HBT Power Amplifier for Mobile Terminals Used in Broadband Wireless Applications

This paper describes technologies of miniaturized high-power low-distortion GaAs HBT power amplifiers with a low-voltage operation for mobile terminals used in 5-6 GHz broadband wireless applications. In conjunction with diode-based linearizing techniques, wideband matching network techniques including trap circuits for second harmonics allow us to obtain a compact broadband power amplifier module with harmonic filtering, achieving the high linear output power at a low supply voltage together with the low distortion and the low second-harmonic spurious outputs in a wide frequency range. The fabricated power amplifier exhibited linear output power levels of 21 and 22 dBm at EVM values of 2.0 and 3.0%, respectively, measured with 54 Mb/s 64-QAM-OFDM signals at a supply voltage of 3.3 V in a frequency range of 5-6 GHz. Second harmonic spurious outputs below -35 dBc were also attained.

A High Efficiency InGaP/GaAs HBT Power Amplifier MMIC for the 5GHz Wireless-LAN Application

An InGaP/GaAs two-stage HBT linear power amplifier MMIC for the 5GHz Wireless-LAN Application was developed. By using a novel linearizer and a small-size via-hole technology, the power amplifier showed high output power (19dBm) with high power-added-efficiency (PAE : 18.5%), sufficient gain (21.0dB) and high linearity (4.78% error vector magnitude : EVM) at supply voltage 3.3V. It is the highest PAE in the power amplifier MMIC for the 5GHz Wireless-LAN application ever reported.

A compact 60 GHz sub-harmonically pumped mixer MMIC integrated with an image rejection filter

In this paper we present a sub-harmonically pumped image-rejection mixer MMIC for antenna-integrated modules in the 60 GHz-band. The mixer MMIC consists of a mixing part and a filter part. The filter has two /spl lambda//2 microstrip resonators and has a mutual-inductive coupling and a capacitive one between its input and output ports, which results in transmission zeros near the pass band. In the mixing part an electrical short circuit for an LO signal is provide by the filter characteristics at an LO frequency instead of a conventional /spl lambda//4-open-stub. The fabricated image-rejection mixer MMIC, of which size is only 1.0 mm/spl times/1.5 mm, shows a conversion loss of 11/spl sim/13 dB and an image rejection ratio of more than 30 dB in a pass-band of 60/spl sim/61.1 GHz when an LO frequency is 29.5 GHz.

Compensation of self-heating effect in DC and pulse characteristics of HBTs

A simple technique to compensate the self-heating effect in DC and pulse characteristics of HBTs is proposed and demonstrated. Due to the cancellation of the positive and negative thermal-electric feedback inside HBTs, the compensation is achieved by inserting a specified resistance in the base bias circuit. An analytical expression specifying the resistance is also presented.

A Patch Antenna Array on a Multi-Layered Ceramic Substrate for 60GHz Applications

In this paper we present a planar antenna structure on a ceramic substrate with intention to integrate with millimeter-wave packages or multi-chip modules. The substrate has two dielectric layers and feed lines between them. We examine the relationship between the antenna performance and the thickness or material of the substrate. In case that the substrate consists of two 150¿m-thick glass ceramic, an antenna gain is more than 20dBi and the bandwidth is about 4GHz for a 64-element antenna. This antenna structure is advantageous because it can be easily integrated with millimeter-wave packages at low cost.

Low Cost Planar Filter for 60GHz Applications

A low-cost printed planar filter circuit on alumina ceramic substrates was developed at 60GHz band. This filter is advantageous in size, cost, and connectivity to MMICs. It is especially suitable for millimeter-wave module integration, where MMICs and filters are all assembled inside one compact package. The trial filter, designed for over 3GHz wide band applications, has less than 4.0dB insertion loss and reasonable rejection performance of S21=15dB/20dB at 1.5GHz/2.0GHz offset frequency from the pass-band.

Multi-Layered Substrates for Wireless Communication Modules at 60GHz

A low-cost module structure for millimeterwave wireless communication is proposed. Hermetically sealed circuits and printed antennas are built on the opposite sides of a multi-layered substrate. Slot-coupled electromagnetic interconnects in multi-layered substrates with more than three layers were investigated experimentally. Broad band 50¿ matching and about 4.6dBi gain were achieved by a single patch antenna directly printed on the ceramic multilayered substrate with high ¿r = 8.9. Suitability of the proposed structure for array antenna design is discussed.

A High-Power Low-Distortion GaAs HBT Power Amplifier with 3.3 V Supply for 5-6 GHz Broadband Wireless Applications

This paper describes a 5-6 GHz band GaAs HBT power amplifier operating at 3.3 V for broadband wireless applications. In conjunction with linearizing circuit techniques, wideband matching circuits including trap circuits for 2nd harmonics allow us to achieve the high linear output power and the low distortion together with low 2nd-harmonic spurious outputs. The fabricated power amplifier exhibited linear output power levels of 21 and 22 dBm at EVM values of 2.0 and 3.0%, respectively, measured with 54 Mbps 64-QAM-OFDM signals. The 2nd harmonic spurious outputs below -35 dBc were also attained