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Stacking of Chip Capacitors and Diodes in Hybrid Front End Circuits

IP.com Disclosure Number: IPCOM000116432D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+3]

Abstract

In the fabrication of RF or microwave hybrid circuits, it is crucial to minimize the number of bonding wires, and if a wire can not be avoided, it is preferred to use a shorter wire. The purpose is to reduce the side effects of uncontrollable antenna lengths generated by excessive or long wire bonds. The side effects include detuned antenna resonance, large stray inductance, and mismatched antenna input impedance, which could significantly impact the performance of the antenna and the RF front-end circuit.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 64% of the total text.

Stacking of Chip Capacitors and Diodes in Hybrid Front End Circuits

      In the fabrication of RF or microwave hybrid circuits, it is
crucial to minimize the number of bonding wires, and if a wire can
not be avoided, it is preferred to use a shorter wire.  The purpose
is to reduce the side effects of uncontrollable antenna lengths
generated by excessive or long wire bonds.  The side effects include
detuned antenna resonance, large stray inductance, and mismatched
antenna input impedance, which could significantly impact the
performance of the antenna and the RF front-end circuit.

      For a high-performance RF front-end circuit, it is not unusual
to use several discrete devices.  For example, in a recent attempt to
build such a circuit on a printed wire antenna, seven devices
including four diodes and three capacitors were required.  The
antenna length is to be determined with an accuracy of less than 20
mils for optimum performance of the antenna/RF front-end assembly.
With more than ten bonding wires, each with a length that is
difficult to control or repeat, there is a high level of uncertainty
in identifying the optimum antenna length.

      Disclosed is a method to overcome this difficulty.  The method
provides a way to construct the antenna/circuit assembly by stacking
the devices (putting one on top of the other), whose contacting sides
are previously connected by bonding wires.  Although not all the
wires can be eliminated, it is a three-dimens...