GaN will play a strong role in advanced RF and microwave applications including 5G and satellite communications. The specifications of these systems will push next-gen GaN devices towards mm-wave operation. The challenges and opportunities for commercial deployment of GaN are identified and a variety of circuit designs are presented. A 5G high-linearity power amplifier MMIC in 0.20um GaN with Pout=36dBm at 51.1% PAE and a Sat-com Ku-band mixer in 0.25um GaN with conversion loss < 10.5dB and IIP3=36.4dBm are demonstrated.

Future directions for GaN in 5G and satellite communications

A short-range terahertz (THz) wireless transmission in the 300 GHz band is demonstrated using low-profile wavelength-scaled dielectric transmitting and receiving cuboid antennas (DCAs). These dielectric cuboid antennas are made of polytetrafluoroethylene with dimensions of approximately 1.2 mm × 1.2 mm × 1.3 mm. The near-field pattern of a DCA at 300 GHz was measured using an electro-optic sensing technique, and its far-field pattern characterization was based on the near-field to far-field transformation. The measured antenna gain was 15.06 ± 0.06 dBi. By employing DCAs as transmitting and receiving antennas, a 17.5 Gbps data transmission rate at distances of approximately 200 and 50 mm with bit error rates of 3.31 × 10^−3 and 7.51 × 10^−7 respectively, is demonstrated. The proposed mesoscopic scale DCA is a promising antenna type in intra-device communications and Kiosk download applications for future mobile devices operating in the 300 GHz band.

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Short-Range Wireless Transmission in the 300 GHz Band Using Low-Profile Wavelength-Scaled Dielectric Cuboid Antennas

A highly linear active mixer in Gallium Nitride on Silicon (GaN-on-Si) monolithic microwave integrated circuit (MMIC) technology, operating in Ka-band for radar applications is introduced. It exhibits a local oscillator (LO) balanced topology of gate-pumped mixers based on high-electron mobility transistors (HEMT) and operates in down-conversion mode. Its design principles and the theoretical foundation of its linearity features resulting from both the high power handling capability of GaN-on-Si HEMTs and the corresponding high applied LO level are presented. An extensive characterization based on excitation of a prototype by broadband continuous wave signals and frequency modulated continuous wave signals validates both the analytical treatment of its linearity and the design of the prototype of the mixer. In the 35–40 GHz operating band, this prototype exhibits a state-of-the-art input referred third order intercept point that reaches 39.1 dBm, and a maximum input referred second order intercept point of 39.4 dBm, with a corresponding conversion gain of −5.2 dB, and LO level of 24 dBm.

A Highly Linear Ka-Band GaN-on-Si Active Balanced Mixer for Radar Applications

A novel concept to launch surface waves at millimeter wave (mmW) frequencies is presented. An on-chip antenna is used to launch a surface wave into an off-chip substrate circumventing the need for a lossy mmW interconnect. As a proof of concept, an on-chip Vivaldi antenna is used to feed the off-chip hologram of a holographic leaky wave antenna. The performance of the antenna is compared to the performance of the same hologram fed by a conventional off-chip surface wave launcher connected by bond wires. Simulation and measurement results are presented and show the advantage of the new concept.

On-Chip Millimeter Wave Surface Wave Launcher for Off-Chip Leaky Wave Antennas

We demonstrate short-range terahertz (THz) wireless transmission using a high-gain and low-profile dielectric cuboid antenna (DCA) in the 300 GHz band The compact DCA will support high-speed mobile user equipment (UE) in the next generation The simple rectangular structure enables easy installation and we configures the current design to a standard waveguide (WR-34) The DCA was developed with polytetrafluoroethylene and has dimensions of 136λ × 136λ × 179λ (136 mm × 136 mm × 179 mm at 300 GHz) Antenna patterns of the DCA at 300 GHz were evaluated using a near-field electro-optic sensing technique The far-field pattern calculated from the measured near-field pattern showed good agreement with simulation results The calculated antenna gain was 155 dBi The wireless transmitter configured with the developed DCA has been demonstrated in the 300 GHz band The resultant data rate with amplitude-shift keying of 175 Gbit/s was achieved at transmission distance of 79 mm

Short-range Wireless Transmitter Using Mesoscopic Dielectric Cuboid Antenna in 300-GHz Band

A down-converter MMIC in 100 nm gate length AlGaN/GaN HEMT technology achieves an input-related 1-dB compression point of 13 dBm at a center frequency of 77 GHz, providing high linearity for radar applications. The single-ended fundamental mixer without preor post-amplification shows 8 dB conversion loss when driven with 13 dBm of LO power within an RF frequency range exceeding 75 to 81 GHz. The high linearity is achieved by operating the GaN transistor as active transconductance mixer, allowing for a high voltage swing of the RF signal even when using a relatively small transistor size as required by the high operating frequency.

High linearity active GaN-HEMT down-converter MMIC for E-band radar applications

A compact receiver MMIC for a 300 GHz wireless communication system has been developed in a 35 nm mHEMT technology. The circuit integrates an active frequency multiplier by three and a buffer amplifier for the LO signal, a single balanced, quadrature, fundamental resistive down-converter and an RF pre-amplifier. The chip measurements have shown that the receiver exhibits a conversion gain of −1 dB and a 3-dB bandwidth of 30 GHz. The DC power consumption of the receiver is 110 mW.

A 300 GHz MMIC-based quadrature receiver for wireless terahertz communications

In this paper, we present the concept and experimental verification of a 240 GHz monolithic integrated frequency modulated continuous wave (FMCW) radar transmitter connected to a planar off-chip frequency scanning antenna. Different wire bond connection options are presented and compared. Simulation and measurement results for the interconnects as well as the overall system are presented. The system works at a center frequency of 240 GHz with a bandwidth of 20 GHz and has a scan range of 8o and a 3 dB-beamwidth of 4o.

Tx front end concept for FMCW radar with frequency scanning antenna at 240 GHz

Millimeter wave radar systems offer several advantages such as the combination of high resolution and the penetration of adverse atmosphere like smoke, dust or rain. This paper presents a monolithic millimeter wave integrated circuit (MMIC) transmitter which offers four channel beam steering capabilities and can be used as a radar or communication system transmitter. At the local oscillator input, in order to simplify packaging, a frequency tripler is used to multiply the 76.6 - 83.3 GHz input signal to the intended 230 - 250 GHz output frequency range. A resistive mixer is used for the conversion of the intermediate frequency signal into the RF domain. The actual beam steering network is realized using an active single pole quadruple throw (SP4T) switch, which is connected to a integrated Butler matrix. The MMIC was fabricated in a 35 nm InGaAs mHEMT process and has a size of 4.0 mm × 1.5 mm

Gulesin Eren

Papers

High linearity active GaN-HEMT down-converter MMIC for E-band radar applications

A 300 GHz MMIC-based quadrature receiver for wireless terahertz communications

Tx front end concept for FMCW radar with frequency scanning antenna at 240 GHz

Quad-channel beam switching WR3-band transmitter MMIC