Vinu Govind

A novel electromagnetic bandgap (EBG) structure for mixed-signal system applications

A novel electromagnetic bandgap (EBG) structure called alternating impedance EBG (AI-EBG) for isolation in mixed-signal systems is proposed. Currently, split planes are usually used for isolation in mixed-signal systems. However, split planes show a poor isolation at high frequencies due to electromagnetic coupling through a gap. This novel EBG structure shows excellent isolation by suppressing almost all possible electromagnetic modes in stopband frequencies. The S-parameter measurements show that this novel EBG structure could suppress noise coupling between RF/analog circuits and digital circuits, especially where a single common power supply is used. Mixed-signal system simulations with and without this novel EBG structure were performed to see improvement of isolation due to this novel EBG structure.

Design of integrated low noise amplifiers (LNA) using embedded passives in organic substrates

The noise figure of a low noise amplifier (LNA) is a function of the quality factor of its inductors. The lack of high-Q inductors in silicon has prevented the development of completely integrated complementary metal oxide semiconductor (CMOS) LNAs for high sensitivity applications like global system for mobile communications (GSM) (1.9 GHz) and wideband code-division multiple-access (W-CDMA) (2.1GHz). Recent developments in the design of high-Q inductors (embedded in low cost integrated circuit (IC) packages) have made single-package integration of RF front-ends feasible. These embedded passives provide a viable alternative to using discrete elements or low-Q on-chip passives, for achieving completely integrated solutions. Compared to on-chip inductors with low Q values and discrete passives with fixed Q/sub s/, the use of these embedded passives also leads to the development of the passive Q as a new variable in circuit design. However, higher Q values also result in new tradeoffs, particularly with respect to device size. This paper presents a novel optimization strategy for the design of completely integrated CMOS LNAs using embedded passives. The tradeoff of higher inductor size for higher Q has been adopted into the LNA design methodology. The paper also presents design issues involved in the use of multiple embedded components in the packaging substrate, particularly with reference to mutual coupling between the passives and reference ground layout.

Noise Isolation in Mixed-Signal Systems Using Alternating Impedance Electromagnetic Bandgap (AI-EBG) Structure-Based Power Distribution Network (PDN)

This paper presents efficient noise isolation and suppression method in mixed-signal systems using alternating impedance electromagnetic bandgap (AI-EBG) structure-based power distribution network (PDN). Currently, split planes are used for isolation in mixed-signal systems for isolating sensitive RF/analog circuits from noisy digital circuits. However, split planes show good isolation only at low frequencies due to electromagnetic coupling through the gap. The AI-EBG structure-based PDN presented in this paper provides excellent isolation (-80 dB ~ -100 dB) in the frequency range of interest by suppressing almost all possible electromagnetic modes. The AI-EBG structure has been integrated into a mixed-signal test vehicle to demonstrate the isolation level achievable. The ability of the AI-EBG structure to suppress switching noise has been quantified in this paper. The AI-EBG structure provided greater than 100 dB of isolation in passive S-parameter measurement and suppressed in-band noise down to -88 dBm of isolation in a functional test.

Isolation in mixed-signal systems using a novel electromagnetic bandgap (EBG) structure

This work presents an efficient isolation method in mixed-signal systems using a novel electromagnetic bandgap (EBG) structure called the alternating impedance EBG (AI-EBG) for isolating sensitive RF/analog circuits from noisy digital circuits. This EBG structure shows excellent isolation by suppressing almost all possible electromagnetic modes in bandgap frequencies. Measurements on a practical mixed-signal system show the feasibility of using this EBG structure to reduce noise coupling between RF/analog circuits and digital circuits, especially where a common power supply is used. To the best of our knowledge, this is the first example of a realistic mixed-signal system employing an EBG-based noise suppression scheme.

Noise reduction and design methodology in mixed-signal systems with alternating impedance electromagnetic bandgap (AI-EBG) structure

This paper presents noise suppression and design methodology in mixed-signal systems with alternating impedance electromagnetic bandgap (AI-EBG) structure. The AI-EBG structure was developed recently and applied for noise isolation/suppression in mixed-signal systems. In this paper, the mixed-signal systems with and without the AI-EBG structure were designed and fabricated to see noise reduction effect due to AI-EBG structure. This AI-EBG structure showed excellent noise suppression in mixed-signal systems by suppressing all harmonic noise peaks due to digital circuits in a stopband range of -100 dB isolation (S/sub 21/) level. However, without carefully designing mixed-signal system with the AI-EBG structure, the use of the AI-EBG structure could cause problems associated with signal integrity as well as electromagnetic interference (EMI). In this paper, excellent noise suppression with AI-EBG structure is shown and design methodology in mixed-signal systems with AI-EBG structure is proposed to avoid possible problems associated with signal integrity as well as EMI.

Near-Field and Far-Field Analyses of Alternating Impedance Electromagnetic Bandgap (AI-EBG) Structure for Mixed-Signal Applications

This paper presents near-field (NF) and far-field (FF) analysis of alternating impedance electromagnetic bandgap (AI-EBG) structure in packages and boards. Three test vehicles have been designed and fabricated for NF and FF measurements. Simulation results using a full-wave solver (SONNET) have been compared with measurement results. This paper investigates the radiation due to return current on different reference planes. The analysis results from simulations and measurements provide important guidelines for design of the AI-EBG structure based power distribution network for noise isolation and suppression in mixed-signal systems

Development of high-k embedded capacitors on printed wiring board using sol-gel and foil-transfer processes

Sol-gel ceramic films were fabricated for organic system-on-package compatible integral capacitor applications. The films were synthesized on Ti and Ni foils which were then transferred onto organic boards using a lamination step. SrTiO/sub 3/ and BaTiO/sub 3/ films were synthesized with capacitance as high as 700 nF/cm/sup 2/ and loss as low as 0.005. It should be noted that the high permeability of Ni (approximately 100 in bulk form) and lower conductivity compared to copper decreases the skin depth and increases the resistivity of copper. This can have a deleterious effect on Q. More studies are underway to investigate this effect.

Design of Novel Highly Integrated Passive Devices for Digital Broadcasting Satellite / 802.11 Home Networking Solution in Liquid Crystal Polymer (LCP) Based Organic Substrates

The use of high performance integrated passive devices (IPD) allows an optimum solution in the tradeoff between integration and flexibility for design modification. The paper presents the integration of sub-circuits into IPDs for WLAN and distributed broadcasting satellite (DBS) applications on liquid polymer crystal (LCP)-based organic substrate technology. An integrated diplexer-coupler-harmonic filter for dual-band WLAN applications and a diplexer-balun chipset for DBS applications are presented. The WLAN IPD measures 5times6mm, exhibits directivities of 27dB and 16dB in the 2.4GHz and 5GHz band, and provides 45dB of second harmonic rejection. The DBS diplexer provides 45dBc rejection. Finally, the 2times1.25mm DBS balun utilizing high-inductive coupling shows a measured amplitude and phase balance of 0.5dB and 5deg and a minimum return loss of 10dB

High Performance and Compact Balanced-Filter Design for WiMAX Front-End Modules (FEM) Using LCP-Based Organic Substrates

In this paper, high performance RF integrated balanced-filters were proposed and designed for single band WiMAX front end application. This FEM includes an on-chip RF power amplifier and one switch, with two receive and one transmit paths. In addition to module size requirement, the WiMAX standard presents several passive design challenges: (1) The power amplifier (PA) provides an increase in rated power, hence a higher transmit gain which forces a more stringent output spurious/harmonic levels specification. (2) Received unwanted signals and blockers levels deplete the linearity performance of the receiver lineup. The module was designed on a multilayer organic (MLO) substrate. The highly integrated, fully shielded RF module incorporates embedded passive components including filters and baluns. Simulated results show excellent electrical performance with low insertion loss, high rejection and good return loss. Additionally, the module exhibits excellent thermal stability over the range of operating parameters.

A multiple frequency signal generator for 802.11a/b/g VoWLAN type applications using organic packaging technology

This paper proposes a signal generator that simultaneously generates multiple frequencies while using the same set of passive components. The first example demonstrates the capability of simultaneously generating 2.45GHz and 5.2 GHz (WLAN a/b/g). Additionally, an oscillator capable of concurrently generating 900 MHz and 1.9 GHz (GSM and DCS-1800 band) is also presented. This paper uses the theory of multi-resonant passives and shows their immediate effects on different topologies of signal generators that generate signals for two or more frequency bands. In addition, measured and simulated results of individual blocks of such a simultaneous signal generator, such as, filters, individual oscillators, and feedback networks, are demonstrated.