Digital vs. analog coherent combining on RL-ESPAR antennas
Juan Carlos Bucheli Garcia, Mohamed Kamoun, Alain Sibille · 2018
The reactively loaded parasitic array radiator (RL-ESPAR) receiver has been acknowledged due to its compactness, fabrication cost and reconfigurability; showing significant beam-forming trade-off capabilities compared to conventional multi-element receiver ends. When used on reception, one relevant problem is to find the value of the reactance loadings to obtain the best signal to noise ratio performance. In the current paper, we compare the performance of digital and analog coherent combining over RL-ESPAR. Particularly, digital combining is realized by virtually rotating such a receiver and then applying the known maximum ratio combining (MRC) technique. On the other hand, analog combining is realized by synthesizing MRC on the reactance loadings via a technique that relies on the simultaneous perturbation stochastic approximation method (SPSA) method (widely applied on ESPAR in the literature). We show that analog combining exceeds digital combining and single dipole reception by around 3 dBs and 4 dBs via the proposed technique, respectively.