APPLICATION NOTE
Design and Implementation of a Miniature
X-Band Edge-Coupled Microstrip BPF Using
AWR Software
Microwave bandpass filters (BPFs) are the fundamental component used in many RF/microwave
applications to eliminate interference from signals operating at nearby frequencies. This
application note presents a straightforward and largely nonmathematical method for designing
an edge-coupled bandpass filter for X-band operations (8.4- 9.3GHz). The flow combines filter
synthesis, closed-form edge-coupled transmission-line models, and electromagnetic (EM)
analysis using the Cadence
®
AWR
®
Microwave Office
®
circuit simulator within Cadence AWR
Design Environment
®
software.
Design Overview
A miniature X-band, edge-coupled microstrip bandpass filter design example demonstrates this flow. The filter was imple-
mented using edge-coupled microstrip lines on a Rogers RO4003 substrate material with Er = 3.66 and H = 8 mil. The
temperature coefficient of dielectric constant was among the lowest of any circuit board material, and the dielectric
constant was stable over a broad frequency range, specifically at X-band frequencies. The simulated results showed good
filter response characteristics with the passband insertion loss approximately 5 dB and return loss greater than 12dB over
the pass bandwidth of 900MHz.
