dBm RF Output Research Articles

Radio Over FSO Communication Using High Optical Alignment Robustness 2D-PDA and its Optical Path Switching Performance

We propose a 30 GHz radio over free-space optical (FSO) communication system for indoor wireless communication applications using a newly developed high-speed photodetector array (PDA) device. The new device performs the role of a photodetector with high optical alignment robustness and also acts as a 30 GHz optical-to-radio converter. Small high-speed photodetectors of 30 mm size are arranged in a 6 × 6 square-shaped alignment to achieve -4.4 dBm RF output at 30 GHz with an external amplifier. A 3-5 dB in-plane RF power distribution in the 4 × 4 PDA region was evaluated. To confirm the proposed concept, a 1 m long radio transmission over a 1.5 m long FSO transmission setup was demonstrated by switching the optical paths. We successfully confirmed a high data rate of up to 21.1 Gbps using several modulation formats under a static optical path switching condition. Additionally, stable and reproducible error vector magnitudes with a range of approximately 9% were recognized during the 10 switching cycles under a dynamic optical path switching condition.

High-Speed and High-Power MUTC Photodiode Working at 1064 nm

We demonstrate low-dark-current, high-speed and high-power back-illuminated flip-chip-bonded modified uni-traveling carrier photodiodes operating at 1064 nm. The photodiodes with $15~\mu \text{m}$ and $18~\mu \text{m}$ diameters achieve 18.6 dBm RF output power at 55 GHz and 19.4 dBm RF output power at 41 GHz, respectively. The bandwidth is analyzed with parameters obtained from S-parameter fitting. There is good agreement between measured and calculated bandwidths.

A low phase noise oscillator based on substrate integrated coaxial line technology

In this article, a miniaturized resonator based on substrate integrated coaxial line technology (SICL) is presented. The SICL resonator consists of a hairpin half-wavelength open-ended coaxial line element and two symmetrical parallel coaxial feed lines. The gap between the feed lines and the hairpin element can be adjusted properly to obtain a steep phase change, which can result in a higher group delay peak and achieve a superior phase noise performance. Based on the proposed SICL resonator, an X-band oscillator has been designed and demonstrated by using low-cost printed circuit boards (PCBs). Great consistency between the measured and simulated results is verified. According to the measured results, the oscillation frequency of the SICL oscillator is 10.0625 GHz with −1.81 dBm RF output power, and the phase noise is −138.6 dBc/Hz@1 MHz. The statistic figure of merit (FOM) is −206.1 dBc/Hz@1 MHz.

High-Power Evanescently Coupled Waveguide MUTC Photodiode With >105-GHz Bandwidth

We demonstrate high-speed and high-power evanescently coupled waveguide integrated modified unitraveling carrier photodiodes. Over 105-GHz bandwidth along with 2 and 1.3 dBm RF output power at 100 and 105 GHz, respectively, has been achieved.

High-Power InP-Based Waveguide Integrated Modified Uni-Traveling-Carrier Photodiodes

We demonstrate monolithic InP-based high-power high-speed waveguide integrated single and balanced modified UTC photodetectors. The single PD chip generates maximum RF output power levels of 8.9 dBm to 5.1 dBm in the frequency range between 60 GHz and 120 GHz. The balanced PD chip has a 3 dB-bandwidth of 80 GHz and generates 2 dBm RF output power at this frequency.

SciFab -a wafer-level heterointegrated InP DHBT/SiGe BiCMOS foundry process for mm-wave applications

We present a wafer-level heterointegrated indium phosphide double heterobipolar transistor on silicon germanium bipolar-complementary metal oxide semiconductor (InP DHBT on SiGe BiCMOS) process which relies on adhesive wafer bonding. Subcircuits are co-designed in both technologies, SiGe BiCMOS and InP DHBT, with more than 300 GHz bandwidth microstrip interconnects. The 250 nm SiGe HBTs offer cutoff frequencies around 200 GHz, the 800 nm InP DHBTs exceed 350 GHz. Heterointegrated signal sources are demonstrated including a 328 GHz quadrupling source with dBm RF output power. A common design kit for full InP DHBT/SiGe BiCMOS co-design was set up. The technology is being opened to third-party customers through IHP's multi-purpose wafer foundry interface. Microphotograph of InP DHBT / SiGe BiCMOS wafer

Improved power conversion efficiency in high-performance photodiodes by flip-chip bonding on diamond

Recently, microwave photonic techniques have emerged to address the challenges that microwave systems face under high-frequency or wideband conditions. To a large extent, the performance of microwave photonic systems depends on the performance of individual optoelectronics devices, such as high-power and high power conversion efficiency photodiodes. Here, we report on a flip chip bonded on a diamond InP/InGaAs modified unitraveling carrier (MUTC) photodiode with record RF output powers of 32.7 dBm (1.86 W), 29.6 dBm, 28.2 dBm, and 26.2 dBm at 10, 15, 20, and 25 GHz, respectively, without active cooling. The corresponding dissipated powers are 34 dBm (2.5 W), 32.3 dBm, 30.4 dBm, and 28.3 dBm, respectively. Compared with previously reported RF power, the device on the diamond submount achieves >80% higher RF output power. Using the high-power and high-frequency MUTC photodiode on diamond submount, a record power conversion efficiency of 50.7%–60% at 6–10 GHz with ∼27.8 dBm RF output power has been achieved as compared to previously reported efficiencies in the <40% range in the corresponding frequency band.

High Power Photodiodes for Microwave Applications

High Power Photodiodes for Microwave Applications

InP-based waveguide photodiodes heterogeneously integrated on silicon-on-insulator for photonic microwave generation

High-linearity modified uni-traveling carrier photodiodes on silicon-on-insulator with low AM-to-PM conversion factor are demonstrated. The devices deliver more than 2.5 dBm RF output power up to 40 GHz and have an output third order intercept point of 30 dBm at 20 GHz. Photodiode arrays exceed a saturation current-bandwidth-product of 630 mA · GHz and reach unsaturated RF output power levels of 10 dBm at 20 GHz.

Thermal Analysis of High-Power InGaAs–InP Photodiodes

InGaAs-InP charge-compensated unitraveling-carrier photodiodes with thick depletion region are demonstrated. A 40-mum-diameter photodiode achieved 10-GHz bandwidth and 24.5dBm RF output power. A 100-mum-diameter photodiode achieved bandwidth of 2 GHz and 29 dBm RF output power. Simulation of the temperature distribution in devices is also presented

A 80–100 GHz image‐reject passive‐HEMT mixer

AbstractThis paper describes a single‐sideband, subharmonically pumped, passive‐HEMT integrated circuit mixer developed for use in transceivers for point‐to‐point telecommunications in the 83–87 GHz band. The gallium arsenide (GaAs) monolithic microwave integrated circuit (MMIC) can readily be fabricated using a standard commercial process. The mixer performs equally well for either up‐ or down‐ conversion. For RF signals in the range 80–100 GHz, the conversion loss is typically 20 dB with LO drive in the range 40–50 GHz. Under these conditions, high rejection of the undesired sideband (&gt;18 dB), relative to the desired signal, is achieved. For up‐conversion, 1 dB compression of the mixer gain typically occurs at −12 dBm RF output power. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2429–2433, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21953

All-digital PLL and transmitter for mobile phones

We present the first all-digital PLL and polar transmitter for mobile phones. They are part of a single-chip GSM/EDGE transceiver SoC fabricated in a 90 nm digital CMOS process. The circuits are architectured from the ground up to be compatible with digital deep-submicron CMOS processes and be readily integrateable with a digital baseband and application processor. To achieve this, we exploit the new paradigm of a deep-submicron CMOS process environment by leveraging on the fast switching times of MOS transistors, the fine lithography and the precise device matching, while avoiding problems related to the limited voltage headroom. The transmitter architecture is fully digital and utilizes the wideband direct frequency modulation capability of the all-digital PLL. The amplitude modulation is realized digitally by regulating the number of active NMOS transistor switches in accordance with the instantaneous amplitude. The conventional RF frequency synthesizer architecture, based on a voltage-controlled oscillator and phase/frequency detector and charge-pump combination, has been replaced with a digitally controlled oscillator and a time-to-digital converter. The transmitter performs GMSK modulation with less than 0.5/spl deg/ rms phase error, -165 dBc/Hz phase noise at 20 MHz offset, and 10 /spl mu/s settling time. The 8-PSK EDGE spectral mask is met with 1.2% EVM. The transmitter occupies 1.5 mm/sup 2/ and consumes 42 mA at 1.2 V supply while producing 6 dBm RF output power.