GPS antenna choice with different price

[yassin.kraouch]

Hi,

i am not an RF specialiste,
please i have a problem in choosing between two GPS antenna, can anyone give me the best one to choose ?
the price is different from the two antenna :

antenna1_1.4SP03AB16182-0010 is about 1.4$

antenna_0.43SP03AE1575 is about 0.43 $

please can you help me to choose between the two antenna ? i need it as soon as possible,

best regards

 

[tony_lth]

What's your requirements?
The 1.4$ have better performance than 0.43$.

 

[yassin.kraouch]

thank you tony_lth i know it has better performance, but what is the prolem of the other antenna ?

 

[E Kafeman]

Both antennas are small high dielectric antennas. They differ from many other types of antennas as they have almost no antenna function. It is the surrounding PCB that acts as antenna. Resulting antenna function will therefore depend on shape and size of your PCB ground plane.
For same reason do I mistrust polarization given in datasheet, as it is more will depend on were on PCB the antenna is placed. Designing PCB and antenna for linear polarization adds 3 dB antenna loss and increases amount of GPS error due to increased noise from indirect signal reflections.
This type of "antennas" can however have a function when antenna space on PCB is limited. Can be complicated to tune at correct center frequency if PCB ground plane is small or less RF stable. Tuning is necessary and a VNA is needed for this job.

 

[yassin.kraouch]

thank you E Kafeman, so you would like to say that the antenna which has the liear polarization is not good ? so i will choose the other antenna who have RHCP polarization, have you any recommendation about the PCB ?

 

[E Kafeman]

Polarization of any of the antennas is more depending on PCB design then actual antenna for both of the antennas. What is printed in datasheet is of less value. It is an antenna advantage if you can design your product to have RHCP. No polarization loss in antenna and correct polarization do also act as a rejection filter for false LHCP signals.

 

[yassin.kraouch]

thank you E Kafeman and sorry for my stupid question, as i said i am not an RF specialiste, so what do you think about the two antenna attached ?

 

[E Kafeman]

A bit simplified, these antennas are not antennas, they are resonators which helps you use PCB ground plane as antenna. Without good RF skills is it not a type of antenna solution I recommend. Some antenna types are plug and play. Place it on PCB and you have decent antenna function. These resonators need skilled placement and tuning. If possible had I not selected none of these. Due to radiation pattern can a patch antenna be to prefer as GPS antenna. Still relative small and a lot easier to handle. An example **broken link removed**.