TYPICALLY REALIZABLE COMPONENTS IN MICS

1
TYPICALLY REALIZABLE COMPONENTS IN MICS

• Passive components
• Low pass,high pass
• Band pass,band stop with medium to large
  bandwidths
• Directional couplers
• Power splitters
• Power combiners
• Circulators,isolators(with ferrite substrates)
• Attenuators
• Resonators
• Transformer circuits
• Branches
• Antennas
• Semiconductor Circuits
• Demodulators
• Receiver and up-converter mixers
• Field effect and bipolar transistor amplifiers
• Transistor-power amplifiers
• Frequency multipliers
• PIN-diode switches

2
FUNCTIONAL COMPONENTS OF A MIC ( FROM A VIEWPOINT
OF A CIRCUIT DEVELOPER )

• Electrical functional units
• Straight-line striplines(e.g. microstrip,coplanar
  lines)
• Stripline discontinuities(e.g. branches,bends,open
  and short circuits)
• Concentrated reactive componentscapacitors,induct
  ors
• Circuit terminations
• High frequency resistances(e.g. attenuators)
• Resistors in bias supplies for semiconductors
• Semi conductorsdiodes,transistors
• Special components(e.g. circulators,dielectric,res
  onators,stripline,antennas)
• Mechanical functional units
• Housing
• High frequency connections
• Dc connections

3
STRUCTURAL COMPONENTS OF A MIC OF A THIN-FILM
HYBRID TYPE( AS SEEN FROM THE TECHNOLOGICAL
STANDPOINT )

• Layered Circuit
• Substrate
• Integrated elements
• Conductor structure
• Resistor structure(with or without alignment)
• (Laminated capacitors)
• Hybrid elements
• Capacitors(e.g. ceramic chips and beam lead
  capacitors)
• Semiconductorsdiodes,transistors(with or
  without packaging)
• Trimmer capacitors and resistors
• Circulators(inserted ferrite disks)
• Dielectric resonators(HDK ceramic blocks)
• Semiflexible miniature coaxial lines
• Connector sections(wires,bands)
• Substrate openings(holes for through-contacts,notc
  hes)
• Plastic coverings and protective covers for
  sensitive hybrid elements
• Packaging
• Individual housing ( hermetically sealed or not)

4
COMPARISON WITH THIN-FILM HYBRID CIRCUIT

• As compared with Al2O3 ceramic thin-film circuits
  GaAs MMICs have the following properties
• Higher upper limiting frequencies and wider
  possible bandwidths due to low reactive
  interconnections
• Better reproducibility of performance due to the
  lack of wire and band connections in the circuit
• Higher packing density,smaller substrate
  sizes,higher miniaturization,higher number of
  circuits(up to 100 per large substrate) in volume
  production
• Cheaper for larger production runs
• No adjustment possible
• Slightly smaller choice of semiconductor
  components(e.g. no IMPATTs) but includes the
  possibility of new circuit concepts(active
  transistor matching,active mixers)
• Investment in equipment necessary
• Harder to develop circuits,so computer aided
  design(CAD) is essential.

5
CRITERIA FOR THE CHOICE OF SUBSTRATE MATERIAL IN
THIN FILM USES

• Reason
• Mechanical loads upon equipment due to shock and
  vibration during use
• Stable package mounting
• Heat removal from components(e.g. power
  transistors)
• Reliability of the circuit
• Reliable packaging(e.g. soldering) over entire
  operating temperature range
• Precise fit in housing to avoid parasitic
  reactance at connector
• Size reduction(high wavelength reduction factor)
• Homogenous circuit parameters
• Reproducible production qualities
• Low temperature dependence of filters and
  resonators
• Low loss circuits,high Q
• Maintenance of circuit operation in damp air
• Low loss circuits

• Required property
• Mechanical carrier for the circuit
• Mechanical stability(robustness)(e.g. against
  breakage)
• Maintenance of shape(no cold flow)
• High thermal conductivity
• Long term stability against environment(temperatur
  e changes,high and low temperature
  storage,dampness,industrial waste gases)
• Thermal expansion similar to that of metals
• Small dimensional variations
• Wave conducting medium
• High er(10-20)
• Er homogeneity
• Small variation in er from sample to sample
• Minimum variation of er with temperature
• Low dielectric loss(tan(delta e) lt 0.001)at
  microwave frequencies
• No water absorption

6

• High electrical insulation strength
• Technological medium
• Stability at high temperatures(1000-2000 degree
  C)
• Chemical reactance
• Flat surface,low cambering
• Smooth surface(indentation depth sigmaeff lt 0.5
  micro m,core size lt 1 micro m)
• Easily workable(drilling and separating)
• Maintenance of shape under pressure
• Surface without defects(e.g. pin holes)
• Thermal expansion coefficient similar to that of
  conductor material
• Commercial and Manufacturing criteria
• Low cost
• Easy to store
• Safe to machine
• Generally available

• Circuits for high powers
• For thin film and thick film technologies and
  soldering(not for simple etching technologies)
• For photo etching techniques
• For high structural accuracy when using
  photomasks
• For high adhesion of thin film conductors
• Through contacts,cutting,and preparation
• For thermo compression and ultra sonic bonding
• For thin film capacitors
• Adhesion of conductors
• Low production costs
• Low production costs
• Low production costs

7
SYSTEM OF INTEGRATED MICS
Circuit Technology Lumped element MICs Distributed MICs (stripline MICs) Substrate Type Plastics(e.g. PTFE) Ceramic Ferrite Sapphire Semiconductor Conductor Type Microstrip Triplate Suspended substrate Finline(mm waves) Dielectrics waveguide(mm waves) Mixed circuits (e.g. microstrip,slotline,coplanar lines)
Technology Simple photolithography(in general,for plastic substrate) Thin film technology Only conductor Conductor R Conductor R C Thick film technology Combined thin film and semi conductor growth technology Semiconductor technology(monolithic MICs) Degree of integration Hybrid circuits Conductor integrated Conductor R integrated Conductor RC integrated Semiconductor or sapphire Monolithic MICs