Carlos A. Donado Morcillo

An Ultra-Thin, High-Power, and Multilayer Organic Antenna Array With T/R Functionality in the

The transmit-receive (T/R) operation of an ultra-thin organic antenna array is presented at a center frequency of 9.5 GHz. High transmit power is achieved while maintaining an ultra-low profile in a novel system-on-a-package scheme whereby 32 silicon-germanium (SiGe), transmit/receive integrated-circuit (TRIC) modules have been flip-chip bonded to the array board. Each SiGe TRIC drives a pair of slot-coupled microstrip patch antennas that form an 8 × 8 rectangular array, which is all packaged in an organic substrate stack of liquid crystal polymer and RT/Duroid 5880LZ. The organic package occupies an area of 30.5 cm × 25.4 cm and has a total thickness of only 1.80 mm. The small-signal characterization of the array showed a G/T=-6.64 dB , and a measured receive gain of 20.1 dB with a variation of 0.7 dB over a 1-GHz bandwidth (BW). Finally, far-field large-signal experiments showed a measured effective isotropically radiated power of 47.1 dBm with a variation of 2.36 dB over the same BW, and without the aid of additional thermal management components.

X

Liquid crystal polymer is a promising substrate for mm-wave packaging. In this work, we present the characterization of liquid crystal polymer from 110 GHz to 170 GHz. The microstrip ring resonator method is used for the relative permittivity and loss tangent extraction at mm-wave frequencies. The effect of radiation loss in the extraction of loss tangent is analyzed through full electromagnetic 3D models to verify that radiation loss can be neglected for the particular geometry under study. The Monte Carlo uncertainty analysis is used to analyze the uncertainty of the method taking into account the uncertainty of each measurement involved in the characterization. Using a frequency dispersive model for the effective permittivity for the microstrip, the relative permittivity of LCP is extracted to be 3.17 and the loss tangent varies from 0.0055 to 0.009. This work is the first to characterize the liquid crystal polymer in D-band.

-Band

The high-power operation of a modular and compact power amplifier (PA) is demonstrated using gallium nitride (GaN) transistors and power-combining networks implemented on an aluminum nitride (AlN) substrate. The power-combining network, tuned for X-Band operation, includes matching circuits and Wilkinson power dividers (WPDs) with tantalum nitride (TaN) thin-film resistors. PA efficiency is increased by minimizing network thermal loss with the AlN substrate, which is an excellent thermal conductor. All system components were mounted on a metal carrier, and were interconnected through gold wire bonds. Large-signal measurements showed power added efficiency (PAE) of 44% and a peak output power of 6.5 W at 9.5 GHz with a 3 dB fractional bandwidth of 14%.

Characterization of liquid crystal polymer from 110 GHz to 170 GHz

This work shows the design of stripline beam-former network components at 9.5 GHz in liquid crystal polymer. Particular emphasis is placed in the implementation of via fences to minimize radiation loss and cross coupling of radio frequency (RF) signals to other bias and digital lines that would feed multiple chips in a single antenna package. Additionally, a Coplanar-Waveguide-to-Stripline transition is presented as a suitable solution for an end-fire RF feed. Measurements of the fabricated striplines showed a normalized return loss better than 20dB over the entire X Band. At 9.5GHz, a line loss of 0.26dB/cm was estimated for the striplines, whereas for the proposed transition, back-to-back measurements showed an insertion loss of 0.42dB.

An X-band GaN HEMT hybrid power amplifier with low-loss Wilkinson division on AlN substrate

RXP is a novel and emerging low loss thin core experimental material that has shown promising results as an RF dielectric substrate. In this paper, Ring Resonator Method was utilized to characterize its dielectric properties (relative permittivity and loss tangent) from 30 to 70 GHz frequency domain. BT, a PCB compatible substrate, and RO3003™, an RF organic material, were also characterized for the purpose of comparison. The measured dielectric constant for RXP4 is found to be stable near 3.13, and the loss tangent remains below 0.005. For RXP1, the dielectric constant averages 4.2, and its loss tangent stays below 0.01. To verify application of RXP at higher frequencies, an aperture-coupled patch antenna was designed at 60 GHz and fabricated using three metal layers. The performance of the antenna was found to be comparable to that of Liquid Crystal Polymer (LCP) substrate. The achieved bandwidth was ~3 GHz, and the gain was around 4.7 dBi (simulation results). The measured bandwidth on the fabricated antenna was ~2 GHz. These results show for the first time that RXP can be a good candidate material for wireless 60 GHz application.

Design of stripline beam-former network components for low-profile, organic phased arrays in the X Band

This paper presents, for the first time, an integrated microfluidic cooling scheme on multilayer organic liquid crystal polymer (LCP) substrate for high power X-band gallium nitride (GaN) devices and amplifiers. The channel is micromachined on LCP and a mixture of water and ethylene glycol is used as a coolant. A 3D electro-thermal model of the microfluidic channel has been created, which illustrates the advantage of having a micro-channel beneath LCP in the case of a static and moving fluid. Measurements were done at 10.5 GHz on a GaN power amplifier (PDC = 1.68 W, PAE = 15 %) that was placed both on LCP and on a microfluidic channel with a static fluid.

Novel low loss thin film materials for wireless 60 GHz application

The design and implementation of a compact, flexible and lightweight X-band transmitter (Tx) module based on high-power gallium nitride (GaN) transistor technology and a low-cost organic package made from liquid crystal polymer (LCP) is presented. In-package measurements of the power amplifier (PA) at 8 GHz show a P.A.E.max of >31%, P1dB of 20 dBm and gain of 11.42 dB. A 4×1 patch antenna array was also fabricated on the same platform. Though no thermal management was used, an effective isotropically radiated power (EIRP) in excess of 20 dBm at 10 GHz was measured for the transmitter module, consisting of only a single-stage PA and antenna array, thus demonstrating that even greater performance can be achieved in the future.

Integrated microfluidic cooling for GaN devices on multilayer organic LCP substrate

This work shows the effect of the conductor surface roughness (CSR) in the measurement of the loss tangent using the microstrip ring resonator method (RRM) in three low-loss, organic dielectric substrates (RT/duroid 6002, 6202 and 5880) and each, with two types of copper metallization. In addition, relative permittivity and loss tangent measurements are presented from 30 GHz to 70 GHz for the three substrates for the first time using the RRM. The copper metallization types used for the study are the rolled metallization with a root mean square (RMS) CSR value of 0.27 um and the Electro-deposited (ED), with an RMS CSR of 1.89 um. Results show that the extracted loss tangent values from the ED metallization are in excellent agreement with the values extracted with a Split Cylinder Cavity at about 34 GHz for all materials studied. On the other hand, the loss tangent values extracted with ring resonators fabricated on a rolled metallization, show errors of about 50%, when compared to those extracted with the same Split-Cylinder cavity. No significant errors were detected in the extracted relative permittivity with the two CSR values, and errors below 6% were achieved when compared to the values extracted with the Split Cylinder method.

A hybrid GaN/organic X-band transmitter module

For the first time, the thermal stability of the dielectric properties, i.e. the relative permittivity and the loss tangent, are presented for RT/duroid® 6002 from 30 GHz to 70 GHz over the temperature range between 20 °C and 200 °C, using the microstrip ring resonator method at two different microstrip impedances. High-frequency-resolution, Multiline TRL calibrations were performed at each temperature point to increase the accuracy of the measurements. Measurements show a remarkably-stable normalized temperature coefficient of the relative permittivity of −17.6 ppm/°C across the entire bandwidth. Likewise, the normalized loss tangent temperature coefficient had a value of about 0.00118 °C−1, with little variations throughout the measurement bandwidth.