Kunia Aihara

Demonstration of Spectral Phase O-CDMA Encoding and Decoding in Monolithically Integrated Arrayed-Waveguide-Grating-Based Encoder

We report on successful spectral phase encoding and decoding operation in a pair of monolithically integrated InP encoder chips, each consisting of an arrayed waveguide grating (AWG) pair and an eight-channel electrooptic phase shifter array. The monolithic fabrication process includes anisotropic reactive ion etching and planarizing hydride-vapor-phase-epitaxy lateral regrowth to realize buried hetero-waveguide structures in AWGs and phase shifters. Electrooptical modulation in the phase shifter arrays in the encoder chip achieved Walsh-code-based optical code-division multiple access (O-CDMA) encoding and decoding. The matched-code encoding-decoding operation resulted in error-free performance in the presence of an interferer, indicating good potential for O-CDMA network applications

Development of Thin-Film Liquid-Crystal-Polymer Surface-Mount Packages for

We present the development of thin-film liquid crystal polymer (LCP) surface mount packages for packaging MMICs in Ka-band. The packages are constructed using multilayer LCP films and can be surface mounted on a printed circuit board. Our experimental results demonstrate that the package feed-through transition including bond wires achieve a return loss of -15 dB at 30 GHz and an insertion loss of less than 1 dB in the Ka-band. With the use of an off-package matching network, we achieve the input return loss of less than ~ -15 dB from 28 GHz to 31 GHz and less than ~ -20 dB from 31 GHz to 36 GHz. The use of LCP enclosure provides the near hermetic capabilities in a compact structure

Ka

We present the development of liquid crystal polymer (LCP) packages and thermal compression sealing processes. We demonstrate the complete process for prototyping, sealing, and assembling a single-chip LCP package at microwave frequencies. Using the thermal compression technique, we achieve a measured fine leak rate of 3.7×10-8 cc-atm/s of a LCP package cavity. We have conducted a series of environmental tests such as temperature cycling and 85°C and 85% humidity. We demonstrated that LCP packages have passed major environmental tests and proved to be a reliable package platform.

-Band Applications

We present the development of a Ka-band receiver module using liquid crystal polymer (LCP) thin-film surface mount packages. The packages are constructed using multi-layer LCP films and can be surface mounted on a printed circuit board (PCB). The package utilizes vias to connect the RF input from the PCB signal launch onto the package substrate. The use of an LCP enclosure provides near-hermetic capabilities in a compact structure. The receiver module consists of a low-noise amplifier (LNA), an image-rejection mixer and a driver amplifier. The surface mount package feedthrough simulation predicts better than 20 dB return loss up to 42 GHz. We show the conversion gain measurement of the receiver and derive a chart that explains sources of loss in the module. From the chart we discern that the package feedthrough loss is approximately 0.7 dB at 38.4 GHz.

Reliability of liquid crystal polymer air cavity packaging

We present the development of molded liquid crystal polymer (LCP) surface mount packages for millimeter wave applications. We show that a coplanar waveguide transmission line on a molded liquid crystal polymer has a measured insertion loss of less than 0.16 dB/mm. The LCP quad flat no-lead (QFN) has demonstrated a return loss of less than -16dB and insertion loss of less than -1.2 dB at 25 GHz.

Development of Multi-Layer Liquid Crystal Polymer Ka-band Receiver Modules

We present the design, development and analysis of electromagnetic microwave resonant carbon nanotube bio-sensors. These bio-sensing sensors consist of circular disk electromagnetic resonant circuits coated with single and multi walled carbon nanotubes (SWNTs and MWNTs) that are highly sensitive to adsorbed bio-molecules. The principle operation of these sensors is based on the changes of resonant frequency when the carbon nanotube interface is exposed to bio-materials. Our initial experimental results demonstrate that resonant frequency of the carbon nanotube resonator sensors changes 2 MHz upon exposure to Isopropanol.

Development of molded liquid crystal polymer surface mount packages for millimeter wave applications

In this paper we present a light weight broadband phased array hybrid receiver module on a multi-layer Liquid Crystal Polymer (LCP) substrate. The phased array module has 8 channels and is designed to operate in the Ka-band, from 32–37 GHz. A broadband linear tapered slot antenna array with a corporate power combiner, chip-on-board MMICs, and all control chips necessary for beam steering are all integrated on a multi-layered near-hermetic LCP substrate. The phased array antenna has a measured bandwidth of 5 GHz with ±30° beam steering capability from boresight, and shows less than 6.75° of beam squint across the full bandwidth of operation. The total size of the array is 100 mm × 100 mm with a board thickness of only 16 mils and weighs only 12.3 grams.

GHz carbon nanotube resonator bio-sensors

This paper presents the design of electrical interconnect for high-speed data transmission involving differential signal vias on printed circuit board (PCB). Between two channels of differential vias, with given intra pair via pitch and spacing from adjacent channel vias, there exists an offset angle where differential crosstalk is minimized. By studying single-ended terms of NEXT and FEXT relation in both time and frequency domain, it becomes clear that such phenomenon occurs once in every quadrant. The crosstalk reduction can be achieved without placing ground vias in between signal vias of two channels, giving more routing space in high-speed PCB designs.

A light weight 8-element broadband phased array receiver on Liquid Crystal Polymer

We report error-free spectral encoding and decoding operation of an InP monolithic, ultra-compact optical-CDMA encoder/decoder photonic chip pair. The experimental results demonstrate the strong potential for realizing high performance O-CDMA networks with InP micro-systems

Minimizing differential crosstalk of vias for high-speed data transmission

We present the development of thin-film Liquid Crystal Polymer (LCP) surface mount packages with a novel bandpass feedthrough at K-band (18 – 27 GHz). The packages are constructed using multi-layer LCP films and can be surface mounted on a printed circuit board. Our experimental results demonstrate that the bandpass package feedthrough transition including bond wires achieve a return loss of 13 dB or higher and an insertion loss of less than 0.5 dB across K-band. The package transition offers 0.2 dB insertion loss and ≫15 dB return loss across X-band, and operates well across 8 – 27 GHz.