Integration Manual
ANNA-B4 series - System integration manual
UBX-21000517 - R03 Contents Page 22 of 76
C1-Public
3 Design-in
3.1 Overview
All application circuits must be properly designed, but there are several points that require special
attention during the application design. A list of these points, in order of importance, follows:
• Select appropriate antenna type and part.
• Antenna circuit affects the RF compliance of the device integrating the module with applicable
certification schemes. Follow the schematic and layout reference design recommendations
provided in this document.
• Select appropriate power supply source and bypass capacitors and carefully route the power
supply nets.
• The power supply circuit might impact the performance of the module. Follow the schematic and
layout design recommendations for Supply interfaces.
• Analog signals are sensitive to noise and should be routed away from high frequency signals.
• High speed interfaces might be a source of noise and can affect compliance with regulatory
standards for radiated emissions. For correct schematic and layout design, see also Universal
asynchronous serial interface (UART) and General layout guidelines.
• System functions like RESET_N, I2C, GPIO, and other system input and output pins, require an
accurate design that can ensure that the voltage level is well defined during module boot.
• Other pins also require an accurate design to ensure proper functionality.
• Make sure not to exceed the electrical specification for any pin.
• When upgrading an existing application design for ANNA-B1 to ANNA-B4, follow the guidelines for
ANNA-B1 to ANNA-B4 migration.
3.2 Antenna integration guidelines
When deciding which antenna concept to implement it is advisable to consider the following
guidelines:
• The antenna design process should begin at the start of the whole product design process. Self-
made PCBs and antenna assembly are useful in estimating overall efficiency and radiation pattern
of the intended design.
• Use antennas designed by an antenna manufacturer providing the best possible return loss (or
VSWR).
• Provide a ground plane large enough according to the related integrated antenna requirements.
The ground plane of the application PCB may be reduced to a minimum size not smaller than one
quarter of wavelength of the minimum frequency the applicable frequency band, however overall
antenna efficiency may benefit from larger ground planes.
Proper placement of the antenna and its surroundings is critical for antenna performance. Avoid
placing the antenna close to conductive or RF-absorbing parts such as metal objects, ferrite
sheets and so on as they may absorb part of the radiated power or shift the resonant frequency
of the antenna or affect the antenna radiation pattern.
• It is highly recommended to strictly follow the detailed and specific guidelines provided by the
antenna manufacturer regarding correct installation and deployment of the antenna system,
including PCB layout and matching circuitry.
• Further to the custom PCB and product restrictions, antennas may require tuning/matching to
comply with all the applicable required certification schemes. It is recommended to consult the
antenna manufacturer for the design-in guidelines and plan the validation activities on the final
prototypes like tuning/matching and performance measures. See Table 12.