UMTS/HSPA+ Module Series
UG89 Hardware Design
UG89_Hardware_Design 45 / 73
WCDMA B5
824~849
869~894
MHz
WCDMA B6
830~840
875~885
MHz
WCDMA B8
880~915
925~960
MHz
4.1.3. Reference Design of RF Antenna Interface
A reference design of RF antenna interface
is recommended as below.
A
π-type matching circuit should
be reserved for better RF performance, and the
π-type
matching components (R1/C1/C2) should be placed
as close to the antenna as possible
. The capacitors are not mounted by default.
ANT_MAIN
R1 0R
C1
NM
C2
NM
Module
Figure 21: Reference Circuit of RF Antenna Interface
UG89 provides an RF antenna pad
for customers’ antenna connection. The RF trace in host PCB
connected to the module
’s RF antenna pad should be micro-strip line or other types of RF traces, whose
characteristic impendence should be close to 50
Ω. UG89 comes with grounding pins which are next to the
antenna pad in order to give a better grounding.
4.1.4. Reference Design of RF Layout
For user’s PCB, the characteristic impedance of all RF traces should be controlled to 50Ω. The impedance
of
the RF traces is usually determined by the trace width (W), the materials’ dielectric constant, height
from the reference ground to the signal layer
(H), and the clearance between RF traces and grounds (S).
Microstrip or coplanar waveguide is typically used in RF layout to control characteristic impedance. The
following are reference designs of microstrip or coplanar waveguide with different PCB structures
