# RF and Microwave Circuit Design: Applications and Theory

We recommend you to submit your preliminary or firm registration at least 4 weeks before course start to ensure a seat on the course.

**TECHNOLOGY FOCUS
** Although RF circuits are generally considered to be
circuits that operate from tens of MHz up to several GHz, and
microwave circuits at frequencies beyond that, boundaries based
purely on frequency are rarely appropriate. Analog integrated
circuits based on lower-frequency design methodologies can now
operate well into the microwave range, purely because of smaller
feature sizes that are now available in CMOS and silicon-germanium
technologies. BiCMOS integrated circuits that operate in the
microwave frequency range, designed using low frequency
architectures, are now abundant.

However, classical microwave circuit design techniques are still
important to model and understand problems arising from noise,
mismatch, circuit losses, and limited bandwidth. We will focus on
the design of discrete circuits that are differentiated from their
historically lower-frequency counterparts by several features. In
RF and microwave design, the phase shift of the component is
significant because its size is comparable with a wavelength, its
reactances and parasitics must be accounted for, and reflections
occur between elements. These all limit bandwidth. We also need to
consider circuit losses that degrade the Q of an element as well as
introduce noise, and nonlinearities that introduce distortion into
the signal path. Electromagnetic radiation and capacitive coupling
will also be features of such circuits. Such 'RF and microwave'
effects are most commonly observed when using discrete or custom
devices, or when assembling integrated circuits together at higher
frequencies into systems.

**COURSE CONTENT
** While focusing on the design of discrete RF and microwave
circuits to show classical microwave design techniques, examples of
integrated circuits are presented to compare the 'two worlds'. As
CMOS design now extends even beyond Ka-band frequencies, many of
these classical microwave design insights and techniques are being
lost. For instance, the use of a source inductor in a CMOS
low-noise amplifier stage is widespread for simultaneously
improving gain and noise match, but why?

Impedance matching, device modelling, circuit stability, power
output, distortion, power combining, and component losses and
parasitics are all examined, using state-of-the-art low-voltage
transistors. This is illustrated in a number of applications such
as small-signal, large-signal, low-noise, and feedback amplifiers
with discrete transistors. Low-noise design considerations are also
introduced, using CAD modelling of reactive and resistive types of
applications. Reflecting its importance as a fundamental building
block of most systems, amplifier design is treated exhaustively,
using both small signal S-parameter methodologies (for noise, gain,
and matching) and large signal models (for power and
distortion).

Oscillators and mixers are also designed to meet demanding systems
requirements. The course first explains the fundamental operating
principles of these components in great simplicity, and then
illustrates the theory elegantly through practice. We show the
importance of modeling parasitic elements that arise in design or
when interconnecting components at high frequencies. We also
consider oscillator and mixer performance using a system simulator,
reviewing how these components need to be specified for use in
communication systems, for instance to maintain I and Q channel
orthogonality, and how this relates to the system performance. We
will also look at higher level RF and microwave subsystems, such as
LNBs and BUCs.

Nonlinear design techniques are also examined with a harmonic
balance simulator, using bipolar, FET, and HEMT devices. The course
emphasises hands-on design and simulation of many circuit types,
considering their linearity, efficiency, and power requirements. We
develop an intuitive understanding of how non-linearity arises, and
its impact on design, together with more detailed circuit modeling
to examine quantitative impact.

To benefit most, bring your own laptop computer, and prior to
attending the course, obtain a free trial license of Microwave
Office (MWO) from AWR at www.awrcorp.com .

Monday

Small-signal RF Circuit Design

To introduce linear active circuits, we review the fundamental
principles of impedance matching and move on to examine the effect
of mismatch on performance.

- Revision of S-parameters, Matching and the Smith Chart
- Gain in a distributed circut - impedance transformation
- Unilateral Gain Circles in Small-signal Amplifier Design
- Complex conjugate matching for maximum gain
- RF Circuit Stability: Graphical and analytical techniques
- K- and µ-Factors, Nyquist Stability Analysis

**Example:** Broadband Transistor Stabilization

- Simultaneous Conjugate Match, Bandwidth Considerations
- GMAX and MSG Definition

**Example:** 1900MHz Amplifier Design for Maximum
Gain

Tuesday

**Discrete Low-Noise and Broadband Amplifiers**

We examine the three commonly used techniques used in maximum
small-signal gain, low-noise, and linear power amplifiers.

- Transducer-, Operating-, and Available-Gain Techniques
- RF Noise Sources, Noise Figure and Noise Measure
- Constant-Noise and Constant-Gain Circles in LNA Design
- Available-Gain Design for Minimum Noise
- Trade-Offs Between Gain, Match, and Noise Performance

**Example:** 900MHz Discrete LNA Design

- Broadband Amplifier Design Techniques
- Reactive Mismatch and Lossy Matching Techniques
- Feedback Amplifiers Combined with Impedance Matching
- Circuit Optimization for Gain, Match and Stability

**Example**: 1-4000 MHz Feedback Amplifier
Design

**Wednesday
**

**Power Amplifier Design**

- Design for Optimal Power - nonlinear circuit analysis
- Quasi-Linear Methods to Achieve Power Matching
- Load Line Characterization
- Load Pull Characterization - Measurement and Prediction
- Classes of Power Amplifiers: A, AB, B, C, and F
- Harmonic Tuning to Optimize Efficiency

**Thursday
**

**Power Amplifier Design (cont'd)**

- Distortion Reduction Techniques

**Example:** Bipolar Power Amplifier Design Example
(CDMA)

**Low Noise (LC) Oscillators**

- Oscillator Design Considerations
- Device - Circuit Interaction (Series and Shunt Resonances)
- Deriving the VCO Tuning Curve
- Phase Noise and its impact on System Performance
- Why a system engineer worries about phase noise

Friday

Low Noise (LC) Oscillators (cont'd)

**Example:** Bipolar Transistor (HBT) VCO Design in
the 4 GHz Band

**Mixer Design**

- Revision of Diode Mixers
- Bipolar and MESFET Mixer Analysis
- Comparison of Mixer Types
- The Importance of Quadrature Balance
- Modulators, Image-Reject, and Single Sideband Mixers

**Example:** FET and Bipolar Transistor Active
Mixer Designs

**Said
about the course from previous participants:
** "Broad knowledge of the teacher."

"Computer simulations to illustrate lecture topics."

"Very good mixture of theory, practical information and simulation."