Except for the reciprocity theorm, transmitting and receiving antennas can live in really different worlds. Many systems use the same antenna for both receiving and transmitting but they hve different issues in a practical communication channel. Antenna beam power pattern (antenna directivity), and maximum power coupling between transmitter and antenna, is the name of the game for transmitting. You want to aim the peak of the beam power pattern in the direction of the intended receiver(s).

with receiving antennas, you must play the signal-to-noise ratio game. That means designing an antenna that does the best job of maximizing the received signal power and minimizing the received noise power. Antenna directive gain can be used to reject noise from spacially narrow sources. However, if the noise power density has a uniform distribution in the spacial sense, increasing the gain of the receiving antenna only increases the noise and signal alike.

There are other reasons for using high gain receiving antennas such as done in astromomy (looking at galaxy or supernova noise) or in military applications where you want to attenuate an intential jammer.

good luck

Dear Carlos,

It depends a little bit on your application, but in very general terms:

For reception, more antenna gain means more power output from the antenna, assuming the antenna points to the transmitter.

More antenna gain also means more directivity, so a better suppression of unwanted signals from other direction. There is a direct relationship between half power beamwidth (HPBW) and directivity. And if the antenna has no losses: between HPBW and antenna gain. A smaller beamwidth means higher directivity. But if you want to receive signals from different directions at the same time, you may need a larger HPBW to cover a wider range of azimuth angles.

A low SWR (Standing Wave Ratio) for transmission means best power transfer from transmitter to antenna. But equally so: best matching between the antenna and the transmission line that goes to the receiver. And best matching means most power at the receiver.

Kindest regards,

  Ben

Dear Carlos,

The antennas are reciprocal, which means that the parameters in transmission and reception are the same.

I recommend reading these lessons antennas are written in Spanish.

http://www.upv.es/antenas/Documentos_PDF/Notas_clase/Tema_1.PDF

Best Regards

Dear Carlos,

I recommend reading very good lectures that can be found in

http://www.ece.mcmaster.ca/faculty/georgieva/antenna_dload/current_lectures/

A precision to Miguel's remark:

The influence of transmission and recpetion is NOT the same if reception is limited by external noise (e.g. HF 3-30 MHz) or interference. In that situation for transmission antenna gain is important, for reception directivity (regardless of efficiency).

The basics of antenna theory call for these standard info. If the antenna is in reception mode. Then high gain means high performance (reception of signals) in a specific direction…the higher the gain the higher the antenna will perform (its sensitivity) in a specific direction…

I guess you mean to write sensitivity….instead of sensibility…..

The rest of the parameters VSWR, HPBW are also somehow related to the gain, in addition to antenna matching losses and dielectric material losses….I hope this gets you started....

Reception Antenna either 'OMNI' or 'Directive', depending upon the application.

In case of omni, generally, HPBW/directivity/Gain are not to expect hence you can ignore. However, for directive reception, these are very important.

VSWR is equally important parameter in both the cases. Of course, if antenna to be used only in a reception mode, little poor SWR will not create problem, as it has to always handle small power.

Sensitivity can be affected by poor SWR as it deteriorates efficiency.

Reception Antenna either 'OMNI' or 'Directive', depending upon the application.

In case of omni, generally, HPBW/directivity/Gain are not to expect hence you can ignore. However, for directive reception, these are very important.

VSWR is equally important parameter in both the cases. Of course, if antenna to be used only in a reception mode, little poor SWR will not create problem, as it has to always handle small power.

Sensitivity can be affected by poor SWR as it deteriorates efficiency.

The parameters; Gain, VSWR, HPBW are important according to applications. Most antennas and based on application need minimum gain should not be less and/or maximum VSWR should not be more and/or certain HPBW. But if you are looking for the receiver sensibility in antenna, then there is another parameter you should take care about; it is the Total Isotropic Sensitivity (TIS).

TIS for the mobile handset is defined as being the input signal power that gives rise to a specific frame error rate or residual bit error rate. The sensitivity is sampled in orthogonal polarization at points spread over a surface surrounding the handset . The TIS is a measure of the handset receiving performance, where both TIS and total radiated power (TRP) together determine the effectiveness of the handset as a piece of radio equipment, in particular the maximum range at which the handset can operate from the base station with some given level of performance. 

The parameter 'Receiver Sensitivity' explains it. A negative value in dbm gives you the receiver sensitivity of a particular module. I can give you an example of XBEE Series 1 and 2. Series 1 and Series 2 module have Receiver sensitivity of -92dbm and -98dbm respectively which means series 2 module has higher receiver sensitivity. The another part of your question deals with Gain, which is a different thing. 

An antenna with a gain of 3 dB means that the power received far from the antenna will be 3 dB higher (twice as much) than what would be received from a loss-less isotropic antenna with the same input power. This deals with directive property of antenna and antenna efficiency. You can follow this link to have a clear view ->

http://www.radio-electronics.com/info/rf-technology-design/rf-noise-sensitivity/receiver-sensitivity-performance-tutorial.php

Except for the reciprocity theorm, transmitting and receiving antennas can live in really different worlds. Many systems use the same antenna for both receiving and transmitting but they hve different issues in a practical communication channel. Antenna beam power pattern (antenna directivity), and maximum power coupling between transmitter and antenna, is the name of the game for transmitting. You want to aim the peak of the beam power pattern in the direction of the intended receiver(s).

with receiving antennas, you must play the signal-to-noise ratio game. That means designing an antenna that does the best job of maximizing the received signal power and minimizing the received noise power. Antenna directive gain can be used to reject noise from spacially narrow sources. However, if the noise power density has a uniform distribution in the spacial sense, increasing the gain of the receiving antenna only increases the noise and signal alike.

There are other reasons for using high gain receiving antennas such as done in astromomy (looking at galaxy or supernova noise) or in military applications where you want to attenuate an intential jammer.

good luck

The parameters you need , dear researcher, should be characteristics of the receiver like the sensibility, the SNR rate before and after demodulation. For the antenna, it's modeled as a filter or radiation/propagated interface.

Dear,

It depends on antenna application. It is not necessary that better gain leads to better sensitivity. An an example, for the mobile phone antenna, it is necessary to get acceptable frequency bandwidth (less than -10 dB) with omin-directionl radiation beam pattern. But these are not enough, we should check that during normal operation, the mobile phone in hand close to head, should keep an acceptable Total Isotropic sensitivity (TIS); in GSM aound -105 dBm and while operation grater by around 10 dBm. Here we can say; In active mode, the entire system efficiency is defined by the total radiated power (TRP) on transmitting (Tx), and the total isotropic sensitivity (TIS) on receiving (Rx). 

in reception, better gain means that signals from main lobe can be transferred to to load; but noise coming from side lobes are important as mentioned by Steve F. Russell

antenna noise temperature is depend on its conductivity and real temperature that cause noise PLUS unwanted radio noises in other directions rather than main beam.