M.F. Davis

Integrated RF architectures in fully-organic SOP technology

Future wireless communications systems require better performance, lower cost, and compact RF front-end footprint. The RF front-end module development and its level of integration are, thus, continuous challenges. In most of the presently used microwave integrated circuit technologies, it is difficult to integrate the passives efficiently with required quality. Another critical obstacle in the design of passive components, which occupy the highest percentage of integrated circuit and circuit board real estate, includes the effort to reduce the module size. These issues can be addressed with multilayer substrate technology. A multilayer organic (MLO)-based process offers the potential as the next generation technology of choice for electronic packaging. It uses a cost effective process, while offering design flexibility and optimized integration due to its multilayer topology. We present the design, model, and measurement data of RF-microwave multilayer transitions and integrated passives implemented in a MLO system on package (SOP) technology. Compact, high Q inductors, and embedded filter designs for wireless module applications are demonstrated for the first time in this technology.

Development of integrated 3D radio front-end system-on-package (SOP)

This paper presents the development and characterization of compact and highly integrated microwave and millimeter wave radio front-end Systems-on-Package (SOP). The three-dimensional transceiver front-end SOP architectures incorporate on-package integrated lumped element passives as well as RF functions primarily filters, baluns, and antennas in standard multi-layer LTCC and fully-organic technologies. An LTCC-based 14 GHz transmitter for satellite outdoor unit, an OC-192 transmitter incorporating Ku-band Optical Sub-Carrier Multiplexing (OSCM) technique as well fully-organic SOP transmission lines and lumped-element components have been demonstrated. These prototypes suggest the feasibility of developing highly miniaturized cost-effective SOP transceivers applicable not only for wireless but also for optoelectronics links.

RF-microwave multi-layer integrated passives using fully organic System on Package (SOP) technology

This paper presents high-density, fully organic multi-layer interconnects and integrated passives for RF and microwave System on Package (SOP) development. The components developed in this technology include novel CPW-microstrip transitions, high Q passives, as well as a planar antenna on a package. High Q passives, designed to be implemented using the featured CPW-microstrip transitions in this organic multi-layer technology, demonstrate the feasibility of implementing SOP technology for RF and microwave applications. This technology also employs a lifted slot antenna with vertical feed to reduce loss at the feeding point and to minimize pattern distortion.

Development of planar antennas in multi-layer packages for RF-system-on-a-package applications

The integration of an antenna with an RF module is an attractive solution for realizing a small size and low cost wireless transceiver. Multi-layer planar antennas for system-on-a-package (SOP) application are presented. Two different types of antennas for the low temperature co-fired ceramic (LTCC) package and the multi-layer organic (MLO) package are developed. For the LTCC package, the cavity-backed patch antenna has been developed, in order to increase bandwidth and to reduce the size of the ground plane. A via feed is used for direct connection with other RF blocks. For the cavity backed patch antenna, bandwidth is increased by 20% and real estate including ground plane is reduced by 50%, compared to the conventional patch antenna. For the MLO package, a lifted slot antenna has been developed. In order to reduce loss at feeding point and to minimize pattern distortion, via feed has been used. The antenna has been designed at 5.8 GHz and has gain of 3.7 dBi and bandwidth of 14%.

Liquid crystal polymer-based integrated passive development for RF applications

A Liquid Crystal Polymer (LCP) based multilayer packaging process is presented for RF/microwave applications. LCP is gaining increasing interest as a choice technology in the packaging community due to its superior thermal and electrical properties including low loss, low dielectric constant and low CTE characteristics. For the first time, we present a thorough study of the design, model, and measurement of integrated passives using LCP. A coplanar waveguide transmission line test structure demonstrates an insertion loss of 0.35 dB at 23 GHz and a return loss better than 15 dB to 30 GHz. Quality factors (Q) in excess of 70 and a self resonance frequency (SRF) to 29 GHz have been achieved. A bandpass filter implementation is also demonstrated to realize a c band module. Advantages of passive integration using built up LCPs as opposed to multilayer organics are discussed.

Multi-layer fully organic-based system on package (SOP) technology for RF applications

We present the development and characterization of multi-layer fully organic-based system-on-package (SOP) technology, referred to as the single level integrated module (SLIM), for RF applications. A multi-layer transceiver architecture and a hybrid microstrip and coplanar waveguide interconnect scheme have been proposed and developed to allow high density interconnects. Coplanar waveguide transmission line test structures have been fabricated on the multi-layer material system and demonstrate an insertion loss of 1.4 dB/in at 13 GHz and a return loss better than 15 dB at 13 GHz.

System-on-Package (SOP) architectures for compact and low cost RF front-end modules

This paper presents the development of advanced System-on-Package (SOP) architectures for compact and low cost wireless RF wireless systems. We present the design of compact stacked patch antennas using SHS structures for LMDS and Vband applications. Multi-layer organic packaging development for SOP is reported. An Intelligent Network Communicator (INC) RF block is presented as example of the high performances of multi-layer organic package. A novel ultra-compact 3D integration technology for SOP-based solutions is proposed and utilized for the implementation of a Ku band VCO module. In addition, the fabrication of very high Qfactor inductors in Liquid Crystal Polymer multi-layer substrate demonstrate superior performances compared to any other multilayer organic packages.

Digital and RF integration in system-on-a-package (SOP)

The Packaging Research Center (PRC) is developing system-on-a-package (SOP) technology, as a complimentary alternative to SOC, as the fundamental building block for next generation convergent systems with computing, telecom and consumer capabilities with data and voice. Any systems of this nature have to provide not only high-speed digital, but also high bandwidth optical, analog, RF and perhaps MEMS functions. The SOP technology being pursued at PRC with embedded digital, optical and RF functions addresses this need, optimizing the IC and the package for functions, performance, cost, size and reliability. The PRC is developing this complimentary alternative to SOC using a three tier strategy consisting of fundamental research innovations, enabling technology developments and system-level testbeds. Individual digital, optical and RF testbeds have been developed to enable the integration of novel packaging technologies like embedded passive and optical components, high density global interconnections and wafer level flip-chip assembly. A phased system testbed is being evolved from these three testbeds to develop new SOP convergent system platforms for a digital/optical/RF system implementation. This paper summarizes the latest PRC accomplishments in the development of SOP baseline processes and system testbeds and updates the progress from basic research and technology integration to system testbeds for SOP.

RF-microwave multi-band design solutions for multilayer organic system on package integrated passives

We present multi-band design solutions for integrated passives using multilayer organic (MLO) process technology for RF and microwave System on Package (SOP) module development. The components developed in this technology include embedded high-Q compact inductors and filters designed in three frequency bands: S, C and Ku applicable for Bluetooth, MMDS, IEEE802.11a WLAN and satellite communications. Measured inductor Q-factor as high as 182 and Self-Resonant-Frequency (SRF) as high as 20 GHz, which represents the highest Q in its frequency range reported to date in a multilayer technology, have been demonstrated. A time domain electromagnetic modeling technique is also use to characterize the passive devices.

A 2.4-GHz radio front end in RF system-on-package technology

Voltage-controlled oscillators (VCOs) are critical components for signal generation and frequency selection in RF/microwave transceivers. Recently, there has been considerable interest in monolithic integration of inductance-capacitance (LC) tank oscillators for highly integrated RF transceivers [1]. Technologies such as Si complimentary metal-oxide-semiconductor (CMOS) and Si/SiGe BiCMOS are of interest in light of the potential for integration with digital functions. The operation of an oscillator can be described using the concept of “negative resistance.” In an oscillator, an active network with negative transconductance, −GM, is connected to an LC-tank circuit with an equivalent parallel resistance, RP. The equivalent negative resistance (1/−GM) looking back into the transconductor is chosen to cancel the equivalent parallel resistance of the tank circuit. RP is obviously related to the quality factor Q of the L and C components. In Si technologies, the Q of the inductor is usually the limiting factor. Differential topologies are advantageous in integrated circuits (ICs) because they offer common-mode rejection. Therefore, differential circuits are less susceptible to supply noise present in on-chip power rails. Many RF integrated circuits (RFICs) utilize double-balanced Gilbert-cell mixers because they offer conversion gain while minimizing local oscillator (LO)/intermediate frequency (IF) feedthrough and even-order mixing products. Differential VCO topologies avoid the need for single-ended to differential conversion circuitry for the LO drive of a Gilbert-cell mixer. Figure 1 shows a differential CMOS complementary −GM oscillator [2], [3]. In this case, the negative resistance seen by the tank is given by